path: root/widgets/misc/e-calendar-item.c

/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */

/* 
 * Author : 
 *  Damon Chaplin <damon@ximian.com>
 *  Bolian Yin <bolian.yin@sun.com>
 *
 * Copyright 2000, Ximian, Inc.
 *
 * This program is free software; you can redistribute it and/or 
 * modify it under the terms of version 2 of the GNU General Public 
 * License as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
 * USA
 */

/*
 * ECalendarItem - canvas item displaying a calendar.
 */


#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include "e-calendar-item.h"
#include "ea-widgets.h"

#include <time.h>
#include <string.h>
#include <glib.h>
#include <gtk/gtkmain.h>
#include <gtk/gtkmenu.h>
#include <gtk/gtkmenuitem.h>
#include <gtk/gtklabel.h>
#include <gtk/gtksignal.h>
#include <gdk/gdkkeysyms.h>
#include <libgnome/gnome-i18n.h>
#include <gal/util/e-util.h>

static const int e_calendar_item_days_in_month[12] = {
    31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
};

#define DAYS_IN_MONTH(year, month) \
  e_calendar_item_days_in_month[month] + (((month) == 1 \
  && ((year) % 4 == 0 && ((year) % 100 != 0 || (year) % 400 == 0))) ? 1 : 0)


static void e_calendar_item_class_init  (ECalendarItemClass *class);
static void e_calendar_item_init    (ECalendarItem   *calitem);
static void e_calendar_item_destroy (GtkObject   *o);
static void e_calendar_item_get_arg (GtkObject   *o,
                     GtkArg      *arg,
                     guint        arg_id);
static void e_calendar_item_set_arg (GtkObject   *o,
                     GtkArg      *arg,
                     guint        arg_id);
static void e_calendar_item_realize (GnomeCanvasItem *item);
static void e_calendar_item_unrealize   (GnomeCanvasItem *item);
static void e_calendar_item_unmap   (GnomeCanvasItem *item);
static void e_calendar_item_update  (GnomeCanvasItem *item,
                     double      *affine,
                     ArtSVP      *clip_path,
                     int          flags);
static void e_calendar_item_draw    (GnomeCanvasItem *item,
                     GdkDrawable     *drawable,
                     int          x,
                     int          y,
                     int          width,
                     int          height);
static void e_calendar_item_draw_month  (ECalendarItem   *calitem,
                     GdkDrawable     *drawable,
                     int          x,
                     int          y,
                     int          width,
                     int          height,
                     int          row,
                     int          col);
static void e_calendar_item_draw_day_numbers (ECalendarItem *calitem,
                          GdkDrawable   *drawable,
                          int        width,
                          int        height,
                          int        row,
                          int        col,
                          int        year,
                          int        month,
                          int        start_weekday,
                          gint       cells_x,
                          gint       cells_y);
static double e_calendar_item_point (GnomeCanvasItem *item,
                     double       x,
                     double       y,
                     int          cx,
                     int          cy,
                     GnomeCanvasItem **actual_item);
static void e_calendar_item_stop_selecting (ECalendarItem *calitem,
                        guint32 time);
static void e_calendar_item_selection_add_days (ECalendarItem *calitem,
                        gint n_days,
                        gboolean multi_selection);
static gint e_calendar_item_key_press_event (ECalendarItem *item,
                         GdkEvent *event);
static gint e_calendar_item_event   (GnomeCanvasItem *item,
                     GdkEvent    *event);
static void e_calendar_item_bounds (GnomeCanvasItem *item, double *x1, double *y1,
                    double *x2, double *y2);

static gboolean e_calendar_item_button_press    (ECalendarItem  *calitem,
                         GdkEvent   *event);
static gboolean e_calendar_item_button_release  (ECalendarItem  *calitem,
                         GdkEvent   *event);
static gboolean e_calendar_item_motion      (ECalendarItem  *calitem,
                         GdkEvent   *event);

static gboolean e_calendar_item_convert_position_to_day (ECalendarItem  *calitem,
                             gint        x,
                             gint        y,
                             gboolean    round_empty_positions,
                             gint       *month_offset,
                             gint       *day,
                             gboolean   *entire_week);
static void e_calendar_item_get_month_info  (ECalendarItem  *calitem,
                         gint        row,
                         gint        col,
                         gint       *first_day_offset,
                         gint       *days_in_month,
                         gint       *days_in_prev_month);
static void e_calendar_item_recalc_sizes(ECalendarItem *calitem);

static void e_calendar_item_get_day_style   (ECalendarItem  *calitem,
                         gint        year,
                         gint        month,
                         gint        day,
                         gint        day_style,
                         gboolean    today,
                         gboolean    prev_or_next_month,
                         gboolean    selected,
                         gboolean    has_focus,
                         gboolean    drop_target,
                         GdkColor      **bg_color,
                         GdkColor      **fg_color,
                         GdkColor      **box_color,
                         gboolean   *bold);
static void e_calendar_item_check_selection_end (ECalendarItem  *calitem,
                         gint        start_month,
                         gint        start_day,
                         gint       *end_month,
                         gint       *end_day);
static void e_calendar_item_check_selection_start(ECalendarItem *calitem,
                          gint      *start_month,
                          gint      *start_day,
                          gint       end_month,
                          gint       end_day);
static void e_calendar_item_add_days_to_selection(ECalendarItem *calitem,
                          gint       days);
static void e_calendar_item_round_up_selection  (ECalendarItem  *calitem,
                         gint       *month_offset,
                         gint       *day);
static void e_calendar_item_round_down_selection (ECalendarItem *calitem,
                          gint      *month_offset,
                          gint      *day);
static gint e_calendar_item_get_inclusive_days  (ECalendarItem  *calitem,
                         gint        start_month_offset,
                         gint        start_day,
                         gint        end_month_offset,
                         gint        end_day);
static void e_calendar_item_ensure_valid_day    (ECalendarItem  *calitem,
                         gint       *month_offset,
                         gint       *day);
static gboolean e_calendar_item_ensure_days_visible (ECalendarItem *calitem,
                             gint start_year,
                             gint start_month,
                             gint start_day,
                             gint end_year,
                             gint end_month,
                             gint end_day,
                             gboolean emission);
static void e_calendar_item_show_popup_menu (ECalendarItem  *calitem,
                         GdkEventButton *event,
                         gint        month_offset);
static void e_calendar_item_on_menu_item_activate(GtkWidget *menuitem,
                          ECalendarItem *calitem);
static void e_calendar_item_position_menu   (GtkMenu            *menu,
                         gint               *x,
                         gint               *y,
                         gboolean           *push_in,
                         gpointer            user_data);
static void e_calendar_item_date_range_changed  (ECalendarItem  *calitem);
static void e_calendar_item_queue_signal_emission   (ECalendarItem  *calitem);
static gboolean e_calendar_item_signal_emission_idle_cb (gpointer data);
static void e_calendar_item_set_selection_if_emission (ECalendarItem    *calitem,
                               GDate        *start_date,
                               GDate        *end_date,
                               gboolean emission);

/* Our arguments. */
enum {
    ARG_0,
    ARG_YEAR,
    ARG_MONTH,
    ARG_X1,
    ARG_Y1,
    ARG_X2,
    ARG_Y2,
    ARG_FONT_DESC,
    ARG_WEEK_NUMBER_FONT,
    ARG_WEEK_NUMBER_FONT_DESC,
    ARG_ROW_HEIGHT,
    ARG_COLUMN_WIDTH,
    ARG_MINIMUM_ROWS,
    ARG_MINIMUM_COLUMNS,
    ARG_MAXIMUM_ROWS,
    ARG_MAXIMUM_COLUMNS,
    ARG_WEEK_START_DAY,
    ARG_SHOW_WEEK_NUMBERS,
    ARG_MAXIMUM_DAYS_SELECTED,
    ARG_DAYS_TO_START_WEEK_SELECTION,
    ARG_MOVE_SELECTION_WHEN_MOVING,
    ARG_ROUND_SELECTION_WHEN_MOVING,
    ARG_DISPLAY_POPUP
};

enum {
  DATE_RANGE_CHANGED,
  SELECTION_CHANGED,
  SELECTION_PREVIEW_CHANGED,
  LAST_SIGNAL
};


static GnomeCanvasItemClass *parent_class;
static guint e_calendar_item_signals[LAST_SIGNAL] = { 0 };


E_MAKE_TYPE (e_calendar_item, "ECalendarItem", ECalendarItem,
         e_calendar_item_class_init, e_calendar_item_init,
         GNOME_TYPE_CANVAS_ITEM)


static void
e_calendar_item_class_init (ECalendarItemClass *class)
{
    GtkObjectClass  *object_class;
    GnomeCanvasItemClass *item_class;

    parent_class = g_type_class_peek_parent (class);

    object_class = GTK_OBJECT_CLASS (class);
    item_class = GNOME_CANVAS_ITEM_CLASS (class);

    gtk_object_add_arg_type ("ECalendarItem::year",
                 GTK_TYPE_INT, GTK_ARG_READWRITE,
                 ARG_YEAR);
    gtk_object_add_arg_type ("ECalendarItem::month",
                 GTK_TYPE_INT, GTK_ARG_READWRITE,
                 ARG_MONTH);
    gtk_object_add_arg_type ("ECalendarItem::x1",
                 GTK_TYPE_DOUBLE, GTK_ARG_READWRITE,
                 ARG_X1);
    gtk_object_add_arg_type ("ECalendarItem::y1",
                 GTK_TYPE_DOUBLE, GTK_ARG_READWRITE,
                 ARG_Y1);
    gtk_object_add_arg_type ("ECalendarItem::x2",
                 GTK_TYPE_DOUBLE, GTK_ARG_READWRITE,
                 ARG_X2);
    gtk_object_add_arg_type ("ECalendarItem::y2",
                 GTK_TYPE_DOUBLE, GTK_ARG_READWRITE,
                 ARG_Y2);
    gtk_object_add_arg_type ("ECalendarItem::font_desc",
                 GTK_TYPE_POINTER, GTK_ARG_READWRITE,
                 ARG_FONT_DESC);
    gtk_object_add_arg_type ("ECalendarItem::week_number_font_desc",
                 GTK_TYPE_POINTER, GTK_ARG_READWRITE,
                 ARG_WEEK_NUMBER_FONT_DESC);
    gtk_object_add_arg_type ("ECalendarItem::row_height",
                 GTK_TYPE_INT, GTK_ARG_READABLE,
                 ARG_ROW_HEIGHT);
    gtk_object_add_arg_type ("ECalendarItem::column_width",
                 GTK_TYPE_INT, GTK_ARG_READABLE,
                 ARG_COLUMN_WIDTH);
    gtk_object_add_arg_type ("ECalendarItem::minimum_rows",
                 GTK_TYPE_INT, GTK_ARG_READWRITE,
                 ARG_MINIMUM_ROWS);
    gtk_object_add_arg_type ("ECalendarItem::minimum_columns",
                 GTK_TYPE_INT, GTK_ARG_READWRITE,
                 ARG_MINIMUM_COLUMNS);
    gtk_object_add_arg_type ("ECalendarItem::maximum_rows",
                 GTK_TYPE_INT, GTK_ARG_READWRITE,
                 ARG_MAXIMUM_ROWS);
    gtk_object_add_arg_type ("ECalendarItem::maximum_columns",
                 GTK_TYPE_INT, GTK_ARG_READWRITE,
                 ARG_MAXIMUM_COLUMNS);
    gtk_object_add_arg_type ("ECalendarItem::week_start_day",
                 GTK_TYPE_INT, GTK_ARG_READWRITE,
                 ARG_WEEK_START_DAY);
    gtk_object_add_arg_type ("ECalendarItem::show_week_numbers",
                 GTK_TYPE_BOOL, GTK_ARG_READWRITE,
                 ARG_SHOW_WEEK_NUMBERS);
    gtk_object_add_arg_type ("ECalendarItem::maximum_days_selected",
                 GTK_TYPE_INT, GTK_ARG_READWRITE,
                 ARG_MAXIMUM_DAYS_SELECTED);
    gtk_object_add_arg_type ("ECalendarItem::days_to_start_week_selection",
                 GTK_TYPE_INT, GTK_ARG_READWRITE,
                 ARG_DAYS_TO_START_WEEK_SELECTION);
    gtk_object_add_arg_type ("ECalendarItem::move_selection_when_moving",
                 GTK_TYPE_BOOL, GTK_ARG_READWRITE,
                 ARG_MOVE_SELECTION_WHEN_MOVING);
    gtk_object_add_arg_type ("ECalendarItem::round_selection_when_moving",
                 GTK_TYPE_BOOL, GTK_ARG_READWRITE,
                 ARG_ROUND_SELECTION_WHEN_MOVING);
    gtk_object_add_arg_type ("ECalendarItem::display_popup",
                 GTK_TYPE_BOOL, GTK_ARG_READWRITE,
                 ARG_DISPLAY_POPUP);

    e_calendar_item_signals[DATE_RANGE_CHANGED] =
        gtk_signal_new ("date_range_changed",
                GTK_RUN_FIRST,
                GTK_CLASS_TYPE (object_class),
                G_STRUCT_OFFSET (ECalendarItemClass, date_range_changed),
                gtk_marshal_NONE__NONE,
                GTK_TYPE_NONE, 0);
    e_calendar_item_signals[SELECTION_CHANGED] =
        gtk_signal_new ("selection_changed",
                GTK_RUN_FIRST,
                GTK_CLASS_TYPE (object_class),
                G_STRUCT_OFFSET (ECalendarItemClass, selection_changed),
                gtk_marshal_NONE__NONE,
                GTK_TYPE_NONE, 0);
    e_calendar_item_signals[SELECTION_PREVIEW_CHANGED] =
        g_signal_new ("selection_preview_changed",
                  G_TYPE_FROM_CLASS (object_class),
                  G_SIGNAL_RUN_LAST,
                  G_STRUCT_OFFSET (ECalendarItemClass, selection_preview_changed),
                  NULL, NULL,
                  g_cclosure_marshal_VOID__VOID,
                  G_TYPE_NONE, 0);

    object_class->destroy = e_calendar_item_destroy;
    object_class->get_arg = e_calendar_item_get_arg;
    object_class->set_arg = e_calendar_item_set_arg;

    /* GnomeCanvasItem method overrides */
    item_class->realize     = e_calendar_item_realize;
    item_class->unrealize   = e_calendar_item_unrealize;
    item_class->unmap   = e_calendar_item_unmap;
    item_class->update      = e_calendar_item_update;
    item_class->draw        = e_calendar_item_draw;
    item_class->point       = e_calendar_item_point;
    item_class->event       = e_calendar_item_event;
    item_class->bounds      = e_calendar_item_bounds;

    class->date_range_changed   = NULL;
    class->selection_changed    = NULL;
    class->selection_preview_changed    = NULL;

    e_calendar_item_a11y_init ();
}


static void
e_calendar_item_init (ECalendarItem *calitem)
{
    struct tm *tmp_tm;
    time_t t;

    /* Set the default time to the current month. */
    t = time (NULL);
    tmp_tm = localtime (&t);
    calitem->year = tmp_tm->tm_year + 1900;
    calitem->month = tmp_tm->tm_mon;

    calitem->styles = NULL;

    calitem->min_cols = 1;
    calitem->min_rows = 1;
    calitem->max_cols = -1;
    calitem->max_rows = -1;

    calitem->rows = 0;
    calitem->cols = 0;

    calitem->show_week_numbers = FALSE;
    calitem->week_start_day = 0;
    calitem->expand = TRUE;
    calitem->max_days_selected = 1;
    calitem->days_to_start_week_selection = -1;
    calitem->move_selection_when_moving = TRUE;
    calitem->round_selection_when_moving = FALSE;
    calitem->display_popup = TRUE;
    
    calitem->x1 = 0.0;
    calitem->y1 = 0.0;
    calitem->x2 = 0.0;
    calitem->y2 = 0.0;

    calitem->selecting = FALSE;
    calitem->selecting_axis = NULL;

    calitem->selection_set = FALSE;

    calitem->selection_changed = FALSE;
    calitem->date_range_changed = FALSE;

    calitem->style_callback = NULL;
    calitem->style_callback_data = NULL;
    calitem->style_callback_destroy = NULL;

    calitem->time_callback = NULL;
    calitem->time_callback_data = NULL;
    calitem->time_callback_destroy = NULL;

    /* Translators: These are the first characters of each day of the
       week, 'M' for 'Monday', 'T' for Tuesday etc. */
    calitem->days = _("MTWTFSS");

    calitem->signal_emission_idle_id = 0;
}


static void
e_calendar_item_destroy     (GtkObject *o)
{
    ECalendarItem *calitem;

    calitem = E_CALENDAR_ITEM (o);

    e_calendar_item_set_style_callback (calitem, NULL, NULL, NULL);
    e_calendar_item_set_get_time_callback (calitem, NULL, NULL, NULL);

    if (calitem->styles) {
        g_free (calitem->styles);
        calitem->styles = NULL;
    }

    if (calitem->signal_emission_idle_id != 0) {
        g_source_remove (calitem->signal_emission_idle_id);
        calitem->signal_emission_idle_id = 0;
    }

    if (calitem->font_desc) {
        pango_font_description_free (calitem->font_desc);
        calitem->font_desc = NULL;
    }

    if (calitem->week_number_font_desc) {
        pango_font_description_free (calitem->week_number_font_desc);
        calitem->week_number_font_desc = NULL;
    }

    if (calitem->selecting_axis)
        g_free (calitem->selecting_axis);
    if (GTK_OBJECT_CLASS (parent_class)->destroy)
        (* GTK_OBJECT_CLASS (parent_class)->destroy) (o);
}


static void
e_calendar_item_get_arg (GtkObject *o, GtkArg *arg, guint arg_id)
{
    GnomeCanvasItem *item;
    ECalendarItem *calitem;

    item = GNOME_CANVAS_ITEM (o);
    calitem = E_CALENDAR_ITEM (o);

    switch (arg_id) {
    case ARG_YEAR:
        GTK_VALUE_INT (*arg) = calitem->year;
        break;
    case ARG_MONTH:
        GTK_VALUE_INT (*arg) = calitem->month;
        break;
    case ARG_X1:
        GTK_VALUE_DOUBLE (*arg) = calitem->x1;
        break;
    case ARG_Y1:
        GTK_VALUE_DOUBLE (*arg) = calitem->y1;
        break;
    case ARG_X2:
        GTK_VALUE_DOUBLE (*arg) = calitem->x2;
        break;
    case ARG_Y2:
        GTK_VALUE_DOUBLE (*arg) = calitem->y2;
        break;
    case ARG_FONT_DESC:
        GTK_VALUE_BOXED (*arg) = calitem->font_desc;
        break;
    case ARG_WEEK_NUMBER_FONT_DESC:
        GTK_VALUE_BOXED (*arg) = calitem->week_number_font_desc;
        break;
    case ARG_ROW_HEIGHT:
        e_calendar_item_recalc_sizes (calitem);
        GTK_VALUE_INT (*arg) = calitem->min_month_height;
        break;
    case ARG_COLUMN_WIDTH:
        e_calendar_item_recalc_sizes (calitem);
        GTK_VALUE_INT (*arg) = calitem->min_month_width;
        break;
    case ARG_MINIMUM_ROWS:
        GTK_VALUE_INT (*arg) = calitem->min_rows;
        break;
    case ARG_MINIMUM_COLUMNS:
        GTK_VALUE_INT (*arg) = calitem->min_cols;
        break;
    case ARG_MAXIMUM_ROWS:
        GTK_VALUE_INT (*arg) = calitem->max_rows;
        break;
    case ARG_MAXIMUM_COLUMNS:
        GTK_VALUE_INT (*arg) = calitem->max_cols;
        break;
    case ARG_WEEK_START_DAY:
        GTK_VALUE_INT (*arg) = calitem->week_start_day;
        break;
    case ARG_SHOW_WEEK_NUMBERS:
        GTK_VALUE_BOOL (*arg) = calitem->show_week_numbers;
        break;
    case ARG_MAXIMUM_DAYS_SELECTED:
        GTK_VALUE_INT (*arg) = e_calendar_item_get_max_days_sel (calitem);
        break;
    case ARG_DAYS_TO_START_WEEK_SELECTION:
        GTK_VALUE_INT (*arg) = e_calendar_item_get_days_start_week_sel (calitem);
        break;
    case ARG_MOVE_SELECTION_WHEN_MOVING:
        GTK_VALUE_BOOL (*arg) = calitem->move_selection_when_moving;
        break;
    case ARG_ROUND_SELECTION_WHEN_MOVING:
        GTK_VALUE_BOOL (*arg) = calitem->round_selection_when_moving;
        break;
    case ARG_DISPLAY_POPUP:
        GTK_VALUE_BOOL (*arg) = e_calendar_item_get_display_popup (calitem);
        break;
    default:
        g_warning ("Invalid arg");
    }
}


static void
e_calendar_item_set_arg (GtkObject *o, GtkArg *arg, guint arg_id)
{
    GnomeCanvasItem *item;
    ECalendarItem *calitem;
    PangoFontDescription *font_desc;
    gboolean need_update = FALSE;
    gdouble dvalue;
    gint ivalue;
    gboolean bvalue;

    item = GNOME_CANVAS_ITEM (o);
    calitem = E_CALENDAR_ITEM (o);
    
    switch (arg_id){
    case ARG_YEAR:
        ivalue = GTK_VALUE_INT (*arg);
        e_calendar_item_set_first_month (calitem, ivalue,
                         calitem->month);
        break;
    case ARG_MONTH:
        ivalue = GTK_VALUE_INT (*arg);
        e_calendar_item_set_first_month (calitem, calitem->year,
                         ivalue);
        break;
    case ARG_X1:
        dvalue = GTK_VALUE_DOUBLE (*arg);
        if (calitem->x1 != dvalue) {
            calitem->x1 = dvalue;
            need_update = TRUE;
        }
        break;
    case ARG_Y1:
        dvalue = GTK_VALUE_DOUBLE (*arg);
        if (calitem->y1 != dvalue) {
            calitem->y1 = dvalue;
            need_update = TRUE;
        }
        break;
    case ARG_X2:
        dvalue = GTK_VALUE_DOUBLE (*arg);
        if (calitem->x2 != dvalue) {
            calitem->x2 = dvalue;
            need_update = TRUE;
        }
        break;
    case ARG_Y2:
        dvalue = GTK_VALUE_DOUBLE (*arg);
        if (calitem->y2 != dvalue) {
            calitem->y2 = dvalue;
            need_update = TRUE;
        }
        break;
    case ARG_FONT_DESC:
        font_desc = GTK_VALUE_BOXED (*arg);
        if (calitem->font_desc)
            pango_font_description_free (calitem->font_desc);
        calitem->font_desc = pango_font_description_copy (font_desc);
        need_update = TRUE;
        break;
    case ARG_WEEK_NUMBER_FONT_DESC:
        font_desc = GTK_VALUE_BOXED (*arg);
        if (calitem->week_number_font_desc)
            pango_font_description_free (calitem->week_number_font_desc);
        calitem->week_number_font_desc = pango_font_description_copy (font_desc);
        need_update = TRUE;
        break;
    case ARG_MINIMUM_ROWS:
        ivalue = GTK_VALUE_INT (*arg);
        ivalue = MAX (1, ivalue);
        if (calitem->min_rows != ivalue) {
            calitem->min_rows = ivalue;
            need_update = TRUE;
        }
        break;
    case ARG_MINIMUM_COLUMNS:
        ivalue = GTK_VALUE_INT (*arg);
        ivalue = MAX (1, ivalue);
        if (calitem->min_cols != ivalue) {
            calitem->min_cols = ivalue;
            need_update = TRUE;
        }
        break;
    case ARG_MAXIMUM_ROWS:
        ivalue = GTK_VALUE_INT (*arg);
        if (calitem->max_rows != ivalue) {
            calitem->max_rows = ivalue;
            need_update = TRUE;
        }
        break;
    case ARG_MAXIMUM_COLUMNS:
        ivalue = GTK_VALUE_INT (*arg);
        if (calitem->max_cols != ivalue) {
            calitem->max_cols = ivalue;
            need_update = TRUE;
        }
        break;
    case ARG_WEEK_START_DAY:
        ivalue = GTK_VALUE_INT (*arg);
        if (calitem->week_start_day != ivalue) {
            calitem->week_start_day = ivalue;
            need_update = TRUE;
        }
        break;
    case ARG_SHOW_WEEK_NUMBERS:
        bvalue = GTK_VALUE_BOOL (*arg);
        if (calitem->show_week_numbers != bvalue) {
            calitem->show_week_numbers = bvalue;
            need_update = TRUE;
        }
        break;
    case ARG_MAXIMUM_DAYS_SELECTED:
        ivalue = GTK_VALUE_INT (*arg);
        e_calendar_item_set_max_days_sel (calitem, ivalue);
        break;
    case ARG_DAYS_TO_START_WEEK_SELECTION:
        ivalue = GTK_VALUE_INT (*arg);
        e_calendar_item_set_days_start_week_sel (calitem, ivalue);
        break;
    case ARG_MOVE_SELECTION_WHEN_MOVING:
        bvalue = GTK_VALUE_BOOL (*arg);
        calitem->move_selection_when_moving = bvalue;
        break;
    case ARG_ROUND_SELECTION_WHEN_MOVING:
        bvalue = GTK_VALUE_BOOL (*arg);
        calitem->round_selection_when_moving = bvalue;
        break;
    case ARG_DISPLAY_POPUP:
        bvalue = GTK_VALUE_BOOL (*arg);
        e_calendar_item_set_display_popup (calitem, bvalue);
        break;
    default:
        g_warning ("Invalid arg");
    }

    if (need_update) {
        gnome_canvas_item_request_update (item);
    }
}

static void
e_calendar_item_realize     (GnomeCanvasItem *item)
{
    ECalendarItem *calitem;
    GdkColormap *colormap;
    gboolean success[E_CALENDAR_ITEM_COLOR_LAST];
    gint nfailed;

    if (GNOME_CANVAS_ITEM_CLASS (parent_class)->realize)
        (* GNOME_CANVAS_ITEM_CLASS (parent_class)->realize) (item);

    calitem = E_CALENDAR_ITEM (item);

    colormap = gtk_widget_get_colormap (GTK_WIDGET (item->canvas));

    calitem->colors[E_CALENDAR_ITEM_COLOR_TODAY_BOX].red   = 65535;
    calitem->colors[E_CALENDAR_ITEM_COLOR_TODAY_BOX].green = 0;
    calitem->colors[E_CALENDAR_ITEM_COLOR_TODAY_BOX].blue  = 0;

    calitem->colors[E_CALENDAR_ITEM_COLOR_SELECTION_FG].red   = 65535;
    calitem->colors[E_CALENDAR_ITEM_COLOR_SELECTION_FG].green = 65535;
    calitem->colors[E_CALENDAR_ITEM_COLOR_SELECTION_FG].blue  = 65535;

    calitem->colors[E_CALENDAR_ITEM_COLOR_SELECTION_BG_FOCUSED].red   = 4700;
    calitem->colors[E_CALENDAR_ITEM_COLOR_SELECTION_BG_FOCUSED].green = 4700;
    calitem->colors[E_CALENDAR_ITEM_COLOR_SELECTION_BG_FOCUSED].blue  = 65535;

    calitem->colors[E_CALENDAR_ITEM_COLOR_SELECTION_BG].red   = 47000;
    calitem->colors[E_CALENDAR_ITEM_COLOR_SELECTION_BG].green = 47000;
    calitem->colors[E_CALENDAR_ITEM_COLOR_SELECTION_BG].blue  = 48000;

    calitem->colors[E_CALENDAR_ITEM_COLOR_PREV_OR_NEXT_MONTH_FG].red   = 47000;
    calitem->colors[E_CALENDAR_ITEM_COLOR_PREV_OR_NEXT_MONTH_FG].green = 47000;
    calitem->colors[E_CALENDAR_ITEM_COLOR_PREV_OR_NEXT_MONTH_FG].blue  = 48000;

    nfailed = gdk_colormap_alloc_colors (colormap, calitem->colors,
                         E_CALENDAR_ITEM_COLOR_LAST, FALSE,
                         TRUE, success);
    if (nfailed)
        g_warning ("Failed to allocate all colors");
}


static void
e_calendar_item_unrealize   (GnomeCanvasItem *item)
{
    ECalendarItem *calitem;
    GdkColormap *colormap;
    gint i;

    calitem = E_CALENDAR_ITEM (item);

    colormap = gtk_widget_get_colormap (GTK_WIDGET (item->canvas));

    for (i = 0; i < E_CALENDAR_ITEM_COLOR_LAST; i++) {
        /* FIXME: gdk_colors_free expects gulong* here but the pixel value in GdkColor
           is guint32.  GDK bug?  */
        gdk_colors_free (colormap, (gulong *) &calitem->colors[i].pixel, 1, 0);
    }

    if (GNOME_CANVAS_ITEM_CLASS (parent_class)->unrealize)
        (* GNOME_CANVAS_ITEM_CLASS (parent_class)->unrealize) (item);
}


static void
e_calendar_item_unmap       (GnomeCanvasItem *item)
{
    ECalendarItem *calitem;

    calitem = E_CALENDAR_ITEM (item);

    if (calitem->selecting) {
        gnome_canvas_item_ungrab (item, GDK_CURRENT_TIME);
        calitem->selecting = FALSE;
    }

    if (GNOME_CANVAS_ITEM_CLASS (parent_class)->unmap)
        (* GNOME_CANVAS_ITEM_CLASS (parent_class)->unmap) (item);
}


static void
e_calendar_item_update      (GnomeCanvasItem *item,
                 double      *affine,
                 ArtSVP      *clip_path,
                 int          flags)
{
    ECalendarItem *calitem;
    GtkStyle *style;
    gint char_height, width, height, space, space_per_cal, space_per_cell;
    gint rows, cols, xthickness, ythickness;
    PangoFontDescription *font_desc;
    PangoContext *pango_context;
    PangoFontMetrics *font_metrics;

    if (GNOME_CANVAS_ITEM_CLASS (parent_class)->update)
        (* GNOME_CANVAS_ITEM_CLASS (parent_class)->update) (item, affine, clip_path, flags);

    calitem = E_CALENDAR_ITEM (item);
    style = GTK_WIDGET (item->canvas)->style;
    xthickness = style->xthickness;
    ythickness = style->ythickness;

    item->x1 = calitem->x1;
    item->y1 = calitem->y1;
    item->x2 = calitem->x2 >= calitem->x1 ? calitem->x2 : calitem->x1;
    item->y2 = calitem->y2 >= calitem->y1 ? calitem->y2 : calitem->y1;

    /* Set up Pango prerequisites */
    font_desc = style->font_desc;
    pango_context = gtk_widget_get_pango_context (GTK_WIDGET (item->canvas));
    font_metrics = pango_context_get_metrics (pango_context, font_desc,
                          pango_context_get_language (pango_context));

    /*
     * Calculate the new layout of the calendar.
     */

    /* Make sure the minimum row width & cell height and the widths of
       all the digits and characters are up to date. */
    e_calendar_item_recalc_sizes (calitem);

    /* Calculate how many rows & cols we can fit in. */
    width = item->x2 - item->x1;
    height = item->y2 - item->y1;

    width -= xthickness * 2;
    height -= ythickness * 2;

    if (calitem->min_month_height == 0)
        rows = 1;
    else
        rows = height / calitem->min_month_height;
    rows = MAX (rows, calitem->min_rows);
    if (calitem->max_rows > 0)
        rows = MIN (rows, calitem->max_rows);

    if (calitem->min_month_width == 0)
        cols = 1;
    else
        cols = width / calitem->min_month_width;
    cols = MAX (cols, calitem->min_cols);
    if (calitem->max_cols > 0)
        cols = MIN (cols, calitem->max_cols);

    if (rows != calitem->rows || cols != calitem->cols)
        e_calendar_item_date_range_changed (calitem);

    calitem->rows = rows;
    calitem->cols = cols;

    /* Split up the empty space according to the configuration.
       If the calendar is set to expand, we divide the space between the
       cells and the spaces around the calendar, otherwise we place the
       calendars in the center of the available area. */

    char_height =
        PANGO_PIXELS (pango_font_metrics_get_ascent (font_metrics)) +
        PANGO_PIXELS (pango_font_metrics_get_descent (font_metrics));

    calitem->month_width = calitem->min_month_width;
    calitem->month_height = calitem->min_month_height;
    calitem->cell_width = calitem->max_digit_width * 2
        + E_CALENDAR_ITEM_MIN_CELL_XPAD;
    calitem->cell_height = char_height
        + E_CALENDAR_ITEM_MIN_CELL_YPAD;
    calitem->month_tpad = 0;
    calitem->month_bpad = 0;
    calitem->month_lpad = 0;
    calitem->month_rpad = 0;

    space = height - calitem->rows * calitem->month_height;
    if (space > 0) {
        space_per_cal = space / calitem->rows;
        calitem->month_height += space_per_cal;

        if (calitem->expand) {
            space_per_cell = space_per_cal / E_CALENDAR_ROWS_PER_MONTH;
            calitem->cell_height += space_per_cell;
            space_per_cal -= space_per_cell * E_CALENDAR_ROWS_PER_MONTH;
        }

        calitem->month_tpad = space_per_cal / 2;
        calitem->month_bpad = space_per_cal - calitem->month_tpad;
    }

    space = width - calitem->cols * calitem->month_width;
    if (space > 0) {
        space_per_cal = space / calitem->cols;
        calitem->month_width += space_per_cal;
        space -= space_per_cal * calitem->cols;

        if (calitem->expand) {
            space_per_cell = space_per_cal / E_CALENDAR_COLS_PER_MONTH;
            calitem->cell_width += space_per_cell;
            space_per_cal -= space_per_cell * E_CALENDAR_COLS_PER_MONTH;
        }

        calitem->month_lpad = space_per_cal / 2;
        calitem->month_rpad = space_per_cal - calitem->month_lpad;
    }

    space = MAX (0, space);
    calitem->x_offset = space / 2;

    gnome_canvas_request_redraw (item->canvas, item->x1, item->y1,
                     item->x2, item->y2);

    pango_font_metrics_unref (font_metrics);
}


/*
 * DRAWING ROUTINES - functions to paint the canvas item.
 */

static void
e_calendar_item_draw        (GnomeCanvasItem *canvas_item,
                 GdkDrawable     *drawable,
                 int          x,
                 int          y,
                 int          width,
                 int          height)
{
    ECalendarItem *calitem;
    GtkStyle *style;
    GdkGC *base_gc, *bg_gc;
    gint char_height, row, col, row_y, bar_height, col_x;
    gint xthickness, ythickness;
    PangoFontDescription *font_desc;
    PangoContext *pango_context;
    PangoFontMetrics *font_metrics;

#if 0
    g_print ("In e_calendar_item_draw %i,%i %ix%i\n",
         x, y, width, height);
#endif
    calitem = E_CALENDAR_ITEM (canvas_item);
    style = GTK_WIDGET (canvas_item->canvas)->style;

    /* Set up Pango prerequisites */
    font_desc = calitem->font_desc;
    if (!font_desc)
        font_desc = style->font_desc;
    pango_context = gtk_widget_get_pango_context (GTK_WIDGET (canvas_item->canvas));
    font_metrics = pango_context_get_metrics (pango_context, font_desc,
                          pango_context_get_language (pango_context));

    char_height =
        PANGO_PIXELS (pango_font_metrics_get_ascent (font_metrics)) +
        PANGO_PIXELS (pango_font_metrics_get_descent (font_metrics));
    xthickness = style->xthickness;
    ythickness = style->ythickness;
    base_gc = style->base_gc[GTK_STATE_NORMAL];
    bg_gc = style->bg_gc[GTK_STATE_NORMAL];

    /* Clear the entire background. */
    gdk_draw_rectangle (drawable, base_gc, TRUE,
                calitem->x1 - x, calitem->y1 - y,
                calitem->x2 - calitem->x1 + 1,
                calitem->y2 - calitem->y1 + 1);

    /* Draw the shadow around the entire item. */
    gtk_draw_shadow (style, drawable,
             GTK_STATE_NORMAL, GTK_SHADOW_IN,
             calitem->x1 - x, calitem->y1 - y,
             calitem->x2 - calitem->x1 + 1,
             calitem->y2 - calitem->y1 + 1);

    row_y = canvas_item->y1 + ythickness;
    bar_height = ythickness * 2
        + E_CALENDAR_ITEM_YPAD_ABOVE_MONTH_NAME + char_height
        + E_CALENDAR_ITEM_YPAD_BELOW_MONTH_NAME;

    for (row = 0; row < calitem->rows; row++) {
        /* Draw the background for the title bars and the shadow around
           it, and the vertical lines between columns. */

        gdk_draw_rectangle (drawable, bg_gc, TRUE,
                    calitem->x1 + xthickness - x, row_y - y,
                    calitem->x2 - calitem->x1 + 1
                    - xthickness * 2,
                    bar_height);

        gtk_draw_shadow (style, drawable,
                 GTK_STATE_NORMAL, GTK_SHADOW_OUT,
                 calitem->x1 + xthickness - x, row_y - y,
                 calitem->x2 - calitem->x1 + 1
                 - xthickness * 2,
                 bar_height);


        for (col = 0; col < calitem->cols; col++) {
            if (col != 0) {
                col_x = calitem->x1 + calitem->x_offset
                    + calitem->month_width * col;
                gtk_draw_vline (style, drawable,
                        GTK_STATE_NORMAL,
                        row_y + ythickness + 1 - y,
                        row_y + bar_height
                        - ythickness - 2 - y,
                        col_x - 1 - x);
            }


            e_calendar_item_draw_month (calitem, drawable, x, y,
                            width, height, row, col);
        }

        row_y += calitem->month_height;
    }

    pango_font_metrics_unref (font_metrics);
}


static void
layout_set_day_text (ECalendarItem *calitem, PangoLayout *layout, int day_index)
{
    char *day;
    int char_size = 0;

    day = g_utf8_offset_to_pointer (calitem->days, day_index);

    /* we use strlen because we actually want to count bytes */
    if (day_index == 6)
        char_size = strlen (day); 
    else
        char_size = strlen (day) - strlen (g_utf8_find_next_char (day, NULL));

    pango_layout_set_text (layout, day, char_size); 
}

static void
e_calendar_item_draw_month  (ECalendarItem   *calitem,
                 GdkDrawable     *drawable,
                 int          x,
                 int          y,
                 int          width,
                 int          height,
                 int          row,
                 int          col)
{
    GnomeCanvasItem *item;
    GtkWidget *widget;
    GtkStyle *style;
    PangoFontDescription *font_desc;
    GdkGC *fg_gc;
    struct tm tmp_tm;
    GdkRectangle clip_rect;
    gint char_height, xthickness, ythickness, start_weekday;
    gint year, month;
    gint month_x, month_y, month_w, month_h;
    gint min_x, max_x, text_x, text_y;
    gint day, day_index, cells_x, cells_y, min_cell_width, text_width;
    gint clip_width, clip_height;
    gchar buffer[64];
    PangoContext *pango_context;
    PangoFontMetrics *font_metrics;
    PangoLayout *layout;

#if 0
    g_print ("In e_calendar_item_draw_month: %i,%i %ix%i row:%i col:%i\n",
         x, y, width, height, row, col);
#endif
    item = GNOME_CANVAS_ITEM (calitem);
    widget = GTK_WIDGET (item->canvas);
    style = widget->style;

    /* Set up Pango prerequisites */
    font_desc = calitem->font_desc;
    if (!font_desc)
        font_desc = style->font_desc;
    pango_context = gtk_widget_get_pango_context (widget);
    font_metrics = pango_context_get_metrics (pango_context, font_desc,
                          pango_context_get_language (pango_context));

    char_height =
        PANGO_PIXELS (pango_font_metrics_get_ascent (font_metrics)) +
        PANGO_PIXELS (pango_font_metrics_get_descent (font_metrics));
    xthickness = style->xthickness;
    ythickness = style->ythickness;
    fg_gc = style->fg_gc[GTK_STATE_NORMAL];

    pango_font_metrics_unref (font_metrics);

    /* Calculate the top-left position of the entire month display. */
    month_x = item->x1 + xthickness + calitem->x_offset
        + col * calitem->month_width - x;
    month_w = item->x2 - item->x1 - xthickness * 2;
    month_w = MIN (month_w, calitem->month_width);
    month_y = item->y1 + ythickness + row * calitem->month_height - y;
    month_h = item->y2 - item->y1 - ythickness * 2;
    month_h = MIN (month_h, calitem->month_height);

    /* Just return if the month is outside the given area. */
    if (month_x >= width || month_x + calitem->month_width <= 0
        || month_y >= height || month_y + calitem->month_height <= 0)
        return;

    month = calitem->month + row * calitem->cols + col;
    year = calitem->year + month / 12;
    month %= 12;

    /* Draw the month name & year, with clipping. Note that the top row
       needs extra space around it for the buttons. */

    layout = gtk_widget_create_pango_layout (widget, NULL);

    if (row == 0 && col == 0)
        min_x = E_CALENDAR_ITEM_XPAD_BEFORE_MONTH_NAME_WITH_BUTTON;
    else
        min_x = E_CALENDAR_ITEM_XPAD_BEFORE_MONTH_NAME;

    max_x = month_w;
    if (row == 0 && col == calitem->cols - 1)
        max_x -= E_CALENDAR_ITEM_XPAD_AFTER_MONTH_NAME_WITH_BUTTON;
    else
        max_x -= E_CALENDAR_ITEM_XPAD_AFTER_MONTH_NAME;

    text_y = month_y + style->ythickness
        + E_CALENDAR_ITEM_YPAD_ABOVE_MONTH_NAME;
    clip_rect.x = month_x + min_x;
    clip_rect.x = MAX (0, clip_rect.x);
    clip_rect.y = MAX (0, text_y);

    memset (&tmp_tm, 0, sizeof (tmp_tm));
    tmp_tm.tm_year = year - 1900;
    tmp_tm.tm_mon = month;
    tmp_tm.tm_mday = 1;
    tmp_tm.tm_isdst = -1;
    mktime (&tmp_tm);
    start_weekday = (tmp_tm.tm_wday + 6) % 7;

    if (month_x + max_x - clip_rect.x > 0) {
        clip_rect.width = month_x + max_x - clip_rect.x;
        clip_rect.height = text_y + char_height - clip_rect.y;
        gdk_gc_set_clip_rectangle (fg_gc, &clip_rect);

        /* This is a strftime() format. %B = Month name, %Y = Year. */
        e_utf8_strftime (buffer, sizeof (buffer), _("%B %Y"), &tmp_tm);

        pango_layout_set_font_description (layout, font_desc);
        pango_layout_set_text (layout, buffer, -1);

        /* Ideally we place the text centered in the month, but we
           won't go to the left of the minimum x position. */
        pango_layout_get_pixel_size (layout, &text_width, NULL);
        text_x = (calitem->month_width - text_width) / 2;
        text_x = MAX (min_x, text_x);

        gdk_draw_layout (drawable, fg_gc,
                 month_x + text_x,
                 text_y,
                 layout);
    }

    /* Set the clip rectangle for the main month display. */
    clip_rect.x = MAX (0, month_x);
    clip_rect.y = MAX (0, month_y);
    clip_width = month_x + month_w - clip_rect.x;
    clip_height = month_y + month_h - clip_rect.y;

    if (clip_width <= 0 || clip_height <= 0) {
        g_object_unref (layout);
        return;
    }

    clip_rect.width = clip_width;
    clip_rect.height = clip_height;

    gdk_gc_set_clip_rectangle (fg_gc, &clip_rect);


    /* Draw the day initials across the top of the month. */
    min_cell_width = calitem->max_digit_width * 2
        + E_CALENDAR_ITEM_MIN_CELL_XPAD;

    cells_x = month_x + E_CALENDAR_ITEM_XPAD_BEFORE_WEEK_NUMBERS + calitem->month_lpad
        + E_CALENDAR_ITEM_XPAD_BEFORE_CELLS;
    if (calitem->show_week_numbers)
        cells_x += calitem->max_week_number_digit_width * 2
            + E_CALENDAR_ITEM_XPAD_AFTER_WEEK_NUMBERS + 1;
    text_x = cells_x + calitem->cell_width
        - (calitem->cell_width - min_cell_width) / 2;
    text_x -= E_CALENDAR_ITEM_MIN_CELL_XPAD / 2;
    text_y = month_y + ythickness * 2
        + E_CALENDAR_ITEM_YPAD_ABOVE_MONTH_NAME
        + char_height + E_CALENDAR_ITEM_YPAD_BELOW_MONTH_NAME
        + E_CALENDAR_ITEM_YPAD_ABOVE_DAY_LETTERS + calitem->month_tpad;

    cells_y = text_y + char_height
        + E_CALENDAR_ITEM_YPAD_BELOW_DAY_LETTERS + 1
        + E_CALENDAR_ITEM_YPAD_ABOVE_CELLS;

    day_index = calitem->week_start_day;
    pango_layout_set_font_description (layout, font_desc);
    for (day = 0; day < 7; day++) {
        layout_set_day_text (calitem, layout, day_index);
        gdk_draw_layout (drawable, fg_gc,
                 text_x - calitem->day_widths [day_index],
                 text_y,
                 layout);

        text_x += calitem->cell_width;
        day_index++;
        if (day_index == 7)
            day_index = 0;
    }


    /* Draw the horizontal line beneath the day initials. */
    gdk_draw_line (drawable, fg_gc,
               cells_x - E_CALENDAR_ITEM_XPAD_BEFORE_CELLS,
               cells_y - E_CALENDAR_ITEM_YPAD_ABOVE_CELLS - 1,
               cells_x + E_CALENDAR_COLS_PER_MONTH * calitem->cell_width - 1,
               cells_y - E_CALENDAR_ITEM_YPAD_ABOVE_CELLS - 1);

    e_calendar_item_draw_day_numbers (calitem, drawable, width, height,
                      row, col, year, month, start_weekday,
                      cells_x, cells_y);

    /* Draw the vertical line after the week number. */
    if (calitem->show_week_numbers) {
        gdk_draw_line (drawable, fg_gc,
                   cells_x - E_CALENDAR_ITEM_XPAD_BEFORE_CELLS - 1,
                   cells_y - E_CALENDAR_ITEM_YPAD_ABOVE_CELLS - 1,
                   cells_x - E_CALENDAR_ITEM_XPAD_BEFORE_CELLS - 1,
                   cells_y + E_CALENDAR_ROWS_PER_MONTH * calitem->cell_height - 1);
    }

    gdk_gc_set_clip_rectangle (fg_gc, NULL);
    g_object_unref (layout);
}


static void
e_calendar_item_draw_day_numbers (ECalendarItem *calitem,
                  GdkDrawable   *drawable,
                  int        width,
                  int        height,
                  int        row,
                  int        col,
                  int        year,
                  int        month,
                  int        start_weekday,
                  gint       cells_x,
                  gint       cells_y)
{
    GnomeCanvasItem *item;
    GtkWidget *widget;
    GtkStyle *style;
    PangoFontDescription *font_desc, *wkfont_desc;
    GdkGC *fg_gc;
    GdkColor *bg_color, *fg_color, *box_color;
    struct tm today_tm;
    time_t t;
    gint char_height, min_cell_width, min_cell_height;
    gint day_num, drow, dcol, day_x, day_y;
    gint text_x, text_y;
    gint num_chars, digit;
    gint week_num, mon, days_from_week_start;
    gint years[3], months[3], days_in_month[3];
    gboolean today, selected, has_focus, drop_target = FALSE;
    gboolean bold, draw_day, finished = FALSE;
    gint today_year, today_month, today_mday, month_offset;
    gchar buffer[2];
    gint day_style = 0;
    PangoContext *pango_context;
    PangoFontMetrics *font_metrics;
    PangoLayout *layout;

    item = GNOME_CANVAS_ITEM (calitem);
    widget = GTK_WIDGET (item->canvas);
    style = widget->style;

    /* Set up Pango prerequisites */
    font_desc = calitem->font_desc;
    if (!font_desc)
        font_desc = style->font_desc;
    wkfont_desc = calitem->week_number_font_desc;
    if (!wkfont_desc)
        wkfont_desc = font_desc;
    fg_gc = style->fg_gc[GTK_STATE_NORMAL];

    pango_context = gtk_widget_get_pango_context (widget);
    font_metrics = pango_context_get_metrics (pango_context, font_desc,
                          pango_context_get_language (pango_context));

    char_height =
        PANGO_PIXELS (pango_font_metrics_get_ascent (font_metrics)) +
        PANGO_PIXELS (pango_font_metrics_get_descent (font_metrics));

    min_cell_width = calitem->max_digit_width * 2
        + E_CALENDAR_ITEM_MIN_CELL_XPAD;
    min_cell_height = char_height + E_CALENDAR_ITEM_MIN_CELL_YPAD;

    layout = gtk_widget_create_pango_layout (widget, NULL);

    /* Calculate the number of days in the previous, current, and next
       months. */
    years[0] = years[1] = years[2] = year;
    months[0] = month - 1;
    months[1] = month;
    months[2] = month + 1;
    if (months[0] == -1) {
        months[0] = 11;
        years[0]--;
    }
    if (months[2] == 12) {
        months[2] = 0;
        years[2]++;
    }

    days_in_month[0] = DAYS_IN_MONTH (years[0], months[0]);
    days_in_month[1] = DAYS_IN_MONTH (years[1], months[1]);
    days_in_month[2] = DAYS_IN_MONTH (years[2], months[2]);

    /* Mon 0 is the previous month, which we may show the end of. Mon 1 is
       the current month, and mon 2 is the next month. */
    mon = 0;

    month_offset = row * calitem->cols + col - 1;
    day_num = days_in_month[0];
    days_from_week_start = (start_weekday + 7 - calitem->week_start_day)
        % 7;
    /* For the top-left month we show the end of the previous month, and
       if the new month starts on the first day of the week we show a
       complete week from the previous month. */
    if (days_from_week_start == 0) {
        if (row == 0 && col == 0) {
            day_num -= 6;
        } else {
            mon++;
            month_offset++;
            day_num = 1;
        }
    } else {
        day_num -= days_from_week_start - 1;
    }

    /* Get today's date, so we can highlight it. */
    if (calitem->time_callback) {
        today_tm = (*calitem->time_callback) (calitem, calitem->time_callback_data);
    } else {
        t = time (NULL);
        today_tm = *localtime (&t);
    }
    today_year = today_tm.tm_year + 1900;
    today_month = today_tm.tm_mon;
    today_mday = today_tm.tm_mday;

    /* We usually skip the last days of the previous month (mon = 0),
       except for the top-left month displayed. */
    draw_day = (mon == 1 || (row == 0 && col == 0));

    for (drow = 0; drow < 6; drow++) {
        /* Draw the week number. */
        if (calitem->show_week_numbers) {
            week_num = e_calendar_item_get_week_number (calitem,
                                    day_num,
                                    months[mon],
                                    years[mon]);

            text_x = cells_x - E_CALENDAR_ITEM_XPAD_BEFORE_CELLS - 1
                - E_CALENDAR_ITEM_XPAD_AFTER_WEEK_NUMBERS;
            text_y = cells_y + drow * calitem->cell_height +
                + (calitem->cell_height - min_cell_height + 1) / 2;

            num_chars = 0;
            if (week_num >= 10) {
                digit = week_num / 10;
                text_x -= calitem->week_number_digit_widths[digit];
                buffer[num_chars++] = digit + '0';
            }

            digit = week_num % 10;
            text_x -= calitem->week_number_digit_widths[digit];
            buffer[num_chars++] = digit + '0';

            gdk_gc_set_foreground (fg_gc,
                           &style->fg[GTK_STATE_NORMAL]);

            pango_layout_set_font_description (layout, wkfont_desc);
            pango_layout_set_text (layout, buffer, num_chars);
            gdk_draw_layout (drawable, fg_gc,
                     text_x,
                     text_y,
                     layout);
        }

        for (dcol = 0; dcol < 7; dcol++) {
            if (draw_day) {
                day_x = cells_x + dcol * calitem->cell_width;
                day_y = cells_y + drow * calitem->cell_height;

                today = years[mon] == today_year
                    && months[mon] == today_month
                    && day_num == today_mday;

                selected = calitem->selection_set
                    && (calitem->selection_start_month_offset < month_offset
                        || (calitem->selection_start_month_offset == month_offset
                        && calitem->selection_start_day <= day_num))
                    && (calitem->selection_end_month_offset > month_offset
                        || (calitem->selection_end_month_offset == month_offset
                        && calitem->selection_end_day >= day_num));

                if (calitem->styles)
                    day_style = calitem->styles[(month_offset + 1) * 32 + day_num];

                /* Get the colors & style to use for the day.*/
                if ((GTK_WIDGET_HAS_FOCUS(item->canvas)) &&
                    item->canvas->focused_item == item)
                    has_focus = TRUE;
                else
                    has_focus = FALSE;

                if (calitem->style_callback)
                    (*calitem->style_callback)
                        (calitem,
                         years[mon],
                         months[mon],
                         day_num,
                         day_style,
                         today,
                         mon != 1,
                         selected,
                         has_focus,
                         drop_target,
                         &bg_color,
                         &fg_color,
                         &box_color,
                         &bold,
                         calitem->style_callback_data);
                else
                    e_calendar_item_get_day_style
                        (calitem,
                         years[mon],
                         months[mon],
                         day_num,
                         day_style,
                         today,
                         mon != 1,
                         selected,
                         has_focus,
                         drop_target,
                         &bg_color,
                         &fg_color,
                         &box_color,
                         &bold);

                /* Draw the background, if set. */
                if (bg_color) {
                    gdk_gc_set_foreground (fg_gc, bg_color);
                    gdk_draw_rectangle (drawable, fg_gc,
                                TRUE,
                                day_x, day_y,
                                calitem->cell_width,
                                calitem->cell_height);
                }

                /* Draw the box, if set. */
                if (box_color) {
                    gdk_gc_set_foreground (fg_gc, box_color);
                    gdk_draw_rectangle (drawable, fg_gc,
                                FALSE,
                                day_x, day_y,
                                calitem->cell_width - 1,
                                calitem->cell_height - 1);
                }

                /* Draw the 1- or 2-digit day number. */
                day_x += calitem->cell_width - (calitem->cell_width - min_cell_width) / 2;
                day_x -= E_CALENDAR_ITEM_MIN_CELL_XPAD / 2;
                day_y += (calitem->cell_height - min_cell_height + 1) / 2;
                day_y += E_CALENDAR_ITEM_MIN_CELL_YPAD / 2;

                num_chars = 0;
                if (day_num >= 10) {
                    digit = day_num / 10;
                    day_x -= calitem->digit_widths[digit];
                    buffer[num_chars++] = digit + '0';
                }

                digit = day_num % 10;
                day_x -= calitem->digit_widths[digit];
                buffer[num_chars++] = digit + '0';

                if (fg_color) {
                    gdk_gc_set_foreground (fg_gc,
                                   fg_color);
                } else {
                    gdk_gc_set_foreground (fg_gc,
                                   &style->fg[GTK_STATE_NORMAL]);
                }

                pango_layout_set_font_description (layout, font_desc);
                pango_layout_set_text (layout, buffer, num_chars);
                gdk_draw_layout (drawable, fg_gc,
                         day_x,
                         day_y,
                         layout);

                /* We use a stupid technique for bold. Just
                   draw it again 1 pixel to the left. */
                if (bold)
                    gdk_draw_layout (drawable, fg_gc,
                             day_x - 1,
                             day_y,
                             layout);
            }

            /* See if we've reached the end of a month. */
            if (day_num == days_in_month[mon]) {
                month_offset++;
                mon++;
                /* We only draw the start of the next month
                   for the bottom-right month displayed. */
                if (mon == 2 && (row != calitem->rows - 1
                         || col != calitem->cols - 1)) {
                    /* Set a flag so we exit the loop. */
                    finished = TRUE;
                    break;
                }
                day_num = 1;
                draw_day = TRUE;
            } else {
                day_num++;
            }
        }

        /* Exit the loop if the flag is set. */
        if (finished)
            break;
    }

    /* Reset the foreground color. */
    gdk_gc_set_foreground (fg_gc, &style->fg[GTK_STATE_NORMAL]);

    g_object_unref (layout);
    pango_font_metrics_unref (font_metrics);
}


gint
e_calendar_item_get_week_number (ECalendarItem *calitem,
                 gint       day,
                 gint       month,
                 gint       year)
{
    GDate date;
    guint weekday, yearday;
    int offset, week_num;
    
    /* FIXME: check what happens at year boundaries. */
    
    g_date_clear (&date, 1);
    g_date_set_dmy (&date, day, month + 1, year);
    
    /* This results in a value of 0 (Monday) - 6 (Sunday). (or -1 on error - oops!!) */
    weekday = g_date_get_weekday (&date) - 1;
    
    /* Calculate the offset from the start of the week. */
    offset = (calitem->week_start_day + 7 - weekday) % 7;
    
    /* Calculate the day of the year, from 0 to 365. */
    yearday = g_date_get_day_of_year (&date) - 1;
    
    /* If the week starts on or after 29th December, it is week 1 of the
       next year, since there are 4 days in the next year. */
    g_date_subtract_days (&date, offset);
    if (g_date_get_month (&date) == 12 && g_date_get_day (&date) >= 29)
        return 1;
    
    /* Calculate the week number, from 0. */
    week_num = (yearday - offset) / 7;
    
    /* If the first week starts on or after Jan 5th, then we need to add
       1 since the previous week will really be the first week. */
    if ((yearday - offset) % 7 >= 4)
        week_num++;
    
    /* Add 1 so week numbers are from 1 to 53. */
    return week_num + 1;
}



/* This is supposed to return the nearest item the the point and the distance.
   Since we are the only item we just return ourself and 0 for the distance.
   This is needed so that we get button/motion events. */
static double
e_calendar_item_point (GnomeCanvasItem *item, double x, double y,
               int cx, int cy,
               GnomeCanvasItem **actual_item)
{
    *actual_item = item;
    return 0.0;
}

static void
e_calendar_item_stop_selecting (ECalendarItem *calitem, guint32 time)
{
    if (!calitem->selecting)
        return;

    gnome_canvas_item_ungrab (GNOME_CANVAS_ITEM (calitem), time);

    calitem->selecting = FALSE;

    /* If the user selects the grayed dates before the first month or
       after the last month, we move backwards or forwards one month.
       The set_month() call should take care of updating the selection. */
    if (calitem->selection_end_month_offset == -1)
        e_calendar_item_set_first_month (calitem, calitem->year,
                         calitem->month - 1);
    else if (calitem->selection_start_month_offset == calitem->rows * calitem->cols)
        e_calendar_item_set_first_month (calitem, calitem->year,
                         calitem->month + 1);

    calitem->selection_changed = TRUE;
    if (calitem->selecting_axis) {
        g_free (calitem->selecting_axis);
        calitem->selecting_axis = NULL;
    }

    e_calendar_item_queue_signal_emission (calitem);
    gnome_canvas_item_request_update (GNOME_CANVAS_ITEM (calitem));
}

static void
e_calendar_item_selection_add_days (ECalendarItem *calitem, gint n_days,
                    gboolean multi_selection)
{
    GDate gdate_start, gdate_end;

    g_return_if_fail (E_IS_CALENDAR_ITEM (calitem));

    if (!e_calendar_item_get_selection (calitem, &gdate_start, &gdate_end)) {
        /* We set the date to the first day of the month */
        g_date_set_dmy (&gdate_start, 1, calitem->month + 1, calitem->year);
        gdate_end = gdate_start;
    }

    if (multi_selection && calitem->max_days_selected > 1) {
        gint days_between;

        days_between = g_date_days_between (&gdate_start, &gdate_end);
        if (!calitem->selecting_axis) {
            calitem->selecting_axis = g_new (GDate, 1);
            *(calitem->selecting_axis) = gdate_start;
        }
        if ((days_between != 0 &&
             g_date_compare (calitem->selecting_axis, &gdate_end) == 0) ||
            (days_between == 0 && n_days < 0)) {
            if (days_between - n_days > calitem->max_days_selected - 1)
                n_days =  days_between + 1 - calitem->max_days_selected;
            g_date_add_days (&gdate_start, n_days);
        }
        else {
            if (days_between + n_days > calitem->max_days_selected - 1)
                n_days = calitem->max_days_selected - 1 - days_between;
            g_date_add_days (&gdate_end, n_days);
        }

        if (g_date_compare (&gdate_end, &gdate_start) < 0) {
            GDate tmp_date;
            tmp_date = gdate_start;
            gdate_start = gdate_end;
            gdate_end = tmp_date;
        }
    }
    else {
        /* clear "selecting_axis", it is only for mulit-selecting */
        if (calitem->selecting_axis) {
            g_free (calitem->selecting_axis);
            calitem->selecting_axis = NULL;
        }
        g_date_add_days (&gdate_start, n_days);
        gdate_end = gdate_start;
    }

    calitem->selecting = TRUE;

    e_calendar_item_set_selection_if_emission (calitem,
                           &gdate_start, &gdate_end,
                           FALSE);
    g_signal_emit_by_name (G_OBJECT (calitem),
                   "selection_preview_changed");
}

static gint
e_calendar_item_key_press_event (ECalendarItem *calitem, GdkEvent *event)
{
    guint keyval = event->key.keyval;
    gboolean multi_selection = FALSE;

    if (event->key.state & GDK_CONTROL_MASK ||
        event->key.state & GDK_MOD1_MASK)
        return FALSE;

    multi_selection = event->key.state & GDK_SHIFT_MASK;
    switch (keyval) {
    case GDK_Up:
        e_calendar_item_selection_add_days (calitem, -7,
                            multi_selection);
        break;
    case GDK_Down:
        e_calendar_item_selection_add_days (calitem, 7,
                            multi_selection);
        break;
    case GDK_Left:
        e_calendar_item_selection_add_days (calitem, -1,
                            multi_selection);
        break;
    case GDK_Right:
        e_calendar_item_selection_add_days (calitem, 1,
                            multi_selection);
        break;
    case GDK_space:
    case GDK_Return:
        e_calendar_item_stop_selecting (calitem, event->key.time);
        break;
    default:
        return FALSE;
    }
    return TRUE;
}

static gint
e_calendar_item_event (GnomeCanvasItem *item, GdkEvent *event)
{
    ECalendarItem *calitem;

    calitem = E_CALENDAR_ITEM (item);

    switch (event->type) {
    case GDK_BUTTON_PRESS:
        return e_calendar_item_button_press (calitem, event);
    case GDK_BUTTON_RELEASE:
        return e_calendar_item_button_release (calitem, event);
    case GDK_MOTION_NOTIFY:
        return e_calendar_item_motion (calitem, event);
    case GDK_FOCUS_CHANGE:
        gnome_canvas_item_request_update (item);
    case GDK_KEY_PRESS:
        return e_calendar_item_key_press_event (calitem, event);
    default:
        break;
    }

    return FALSE;
}

static void
e_calendar_item_bounds (GnomeCanvasItem *item, double *x1, double *y1,
            double *x2, double *y2)
{
    ECalendarItem *calitem;

    g_return_if_fail (E_IS_CALENDAR_ITEM (item));

    calitem = E_CALENDAR_ITEM (item);
    *x1 = calitem->x1;
    *y1 = calitem->y1;
    *x2 = calitem->x2;
    *y2 = calitem->y2;
}

/* This checks if any fonts have changed, and if so it recalculates the
   text sizes and the minimum month size. */
static void
e_calendar_item_recalc_sizes        (ECalendarItem *calitem)
{
    GnomeCanvasItem *canvas_item;
    GtkStyle *style;
    gchar *digits = "0123456789";
    gint day, digit, max_digit_width, max_week_number_digit_width;
    gint char_height, width, min_cell_width, min_cell_height;
    PangoFontDescription *font_desc, *wkfont_desc;
    PangoContext *pango_context;
    PangoFontMetrics *font_metrics;
    PangoLayout *layout;

    canvas_item = GNOME_CANVAS_ITEM (calitem);
    style = GTK_WIDGET (canvas_item->canvas)->style;

    if (!style)
        return;

    /* Set up Pango prerequisites */
    font_desc = calitem->font_desc;
    wkfont_desc = calitem->week_number_font_desc;
    if (!font_desc)
        font_desc = style->font_desc;

    pango_context = gtk_widget_create_pango_context (GTK_WIDGET (canvas_item->canvas));
    font_metrics = pango_context_get_metrics (pango_context, font_desc,
                          pango_context_get_language (pango_context));
    layout = pango_layout_new (pango_context);


    char_height =
        PANGO_PIXELS (pango_font_metrics_get_ascent (font_metrics)) +
        PANGO_PIXELS (pango_font_metrics_get_descent (font_metrics));

    for (day = 0; day < 7; day++) {
        layout_set_day_text (calitem, layout, day);
        pango_layout_get_pixel_size (layout, &calitem->day_widths [day], NULL);
    }

    max_digit_width = 0;
    max_week_number_digit_width = 0;
    for (digit = 0; digit < 10; digit++) {
        pango_layout_set_text (layout, &digits [digit], 1);
        pango_layout_get_pixel_size (layout, &width, NULL);

        calitem->digit_widths[digit] = width;
        max_digit_width = MAX (max_digit_width, width);

        if (wkfont_desc) {
            pango_context_set_font_description (pango_context, wkfont_desc);
            pango_layout_context_changed (layout);

            pango_layout_set_text (layout, &digits [digit], 1);
            pango_layout_get_pixel_size (layout, &width, NULL);

            calitem->week_number_digit_widths[digit] = width;
            max_week_number_digit_width = MAX (max_week_number_digit_width, width);

            pango_context_set_font_description (pango_context, font_desc);
            pango_layout_context_changed (layout);
        } else {
            calitem->week_number_digit_widths[digit] = width;
            max_week_number_digit_width = max_digit_width;
        }
    }
    calitem->max_digit_width = max_digit_width;
    calitem->max_week_number_digit_width = max_week_number_digit_width;

    min_cell_width = calitem->max_digit_width * 2
        + E_CALENDAR_ITEM_MIN_CELL_XPAD;
    min_cell_height = char_height + E_CALENDAR_ITEM_MIN_CELL_YPAD;

    calitem->min_month_width = E_CALENDAR_ITEM_XPAD_BEFORE_WEEK_NUMBERS
        + E_CALENDAR_ITEM_XPAD_BEFORE_CELLS + min_cell_width * 7
        + E_CALENDAR_ITEM_XPAD_AFTER_CELLS;
    if (calitem->show_week_numbers) {
        calitem->min_month_width += calitem->max_week_number_digit_width * 2
            + E_CALENDAR_ITEM_XPAD_AFTER_WEEK_NUMBERS + 1;
    }

    calitem->min_month_height = style->ythickness * 2
        + E_CALENDAR_ITEM_YPAD_ABOVE_MONTH_NAME + char_height
        + E_CALENDAR_ITEM_YPAD_BELOW_MONTH_NAME + 1
        + E_CALENDAR_ITEM_YPAD_ABOVE_DAY_LETTERS
        + char_height + E_CALENDAR_ITEM_YPAD_BELOW_DAY_LETTERS + 1
        + E_CALENDAR_ITEM_YPAD_ABOVE_CELLS + min_cell_height * 6
        + E_CALENDAR_ITEM_YPAD_BELOW_CELLS;

    g_object_unref (layout);
    g_object_unref (pango_context);
    pango_font_metrics_unref (font_metrics);
}


static void
e_calendar_item_get_day_style       (ECalendarItem  *calitem,
                     gint        year,
                     gint        month,
                     gint        day,
                     gint        day_style,
                     gboolean    today,
                     gboolean    prev_or_next_month,
                     gboolean    selected,
                     gboolean    has_focus,
                     gboolean    drop_target,
                     GdkColor      **bg_color,
                     GdkColor      **fg_color,
                     GdkColor      **box_color,
                     gboolean   *bold)
{
    *bg_color = NULL;
    *fg_color = NULL;
    *box_color = NULL;
    *bold = FALSE;

    if (day_style == 1)
        *bold = TRUE;

    if (today)
        *box_color = &calitem->colors[E_CALENDAR_ITEM_COLOR_TODAY_BOX];

    if (prev_or_next_month)
        *fg_color = &calitem->colors[E_CALENDAR_ITEM_COLOR_PREV_OR_NEXT_MONTH_FG];

    if (selected) {
        *fg_color = &calitem->colors[E_CALENDAR_ITEM_COLOR_SELECTION_FG];
        if (has_focus)
            *bg_color = &calitem->colors[E_CALENDAR_ITEM_COLOR_SELECTION_BG_FOCUSED];
        else
            *bg_color = &calitem->colors[E_CALENDAR_ITEM_COLOR_SELECTION_BG];

    }
}



static gboolean
e_calendar_item_button_press    (ECalendarItem  *calitem,
                 GdkEvent   *event)
{
    gint month_offset, day;
    gboolean all_week, round_up_end = FALSE, round_down_start = FALSE;

    if (event->button.button == 4)
        e_calendar_item_set_first_month (calitem, calitem->year,
                         calitem->month - 1);
    else if (event->button.button == 5)
        e_calendar_item_set_first_month (calitem, calitem->year,
                         calitem->month + 1);

    if (!e_calendar_item_convert_position_to_day (calitem,
                              event->button.x,
                              event->button.y,
                              TRUE,
                              &month_offset, &day,
                              &all_week))
        return FALSE;

    if (event->button.button == 3 && day == -1 
        && e_calendar_item_get_display_popup (calitem)) {
        e_calendar_item_show_popup_menu (calitem,
                         (GdkEventButton*) event,
                         month_offset);
        return TRUE;
    }

    if (event->button.button != 1 || day == -1)
        return FALSE;

    if (calitem->max_days_selected < 1)
        return TRUE;

    if (gnome_canvas_item_grab (GNOME_CANVAS_ITEM (calitem),
                    GDK_POINTER_MOTION_MASK
                    | GDK_BUTTON_RELEASE_MASK,
                    NULL, event->button.time) != 0)
        return FALSE;

    calitem->selection_set = TRUE;
    calitem->selection_start_month_offset = month_offset;
    calitem->selection_start_day = day;
    calitem->selection_end_month_offset = month_offset;
    calitem->selection_end_day = day;

    calitem->selection_real_start_month_offset = month_offset;
    calitem->selection_real_start_day = day;

    calitem->selection_from_full_week = FALSE;
    calitem->selecting = TRUE;
    calitem->selection_dragging_end = TRUE;

    if (all_week) {
        calitem->selection_from_full_week = TRUE;
        round_up_end = TRUE;
    }

    if (calitem->days_to_start_week_selection == 1) {
        round_down_start = TRUE;
        round_up_end = TRUE;
    }

    /* Don't round up or down if we can't select a week or more. */
    if (calitem->max_days_selected < 7) {
        round_down_start = FALSE;
        round_up_end = FALSE;
    }

    if (round_up_end)
        e_calendar_item_round_up_selection (calitem, &calitem->selection_end_month_offset, &calitem->selection_end_day);

    if (round_down_start)
        e_calendar_item_round_down_selection (calitem, &calitem->selection_start_month_offset, &calitem->selection_start_day);

    gnome_canvas_item_request_update (GNOME_CANVAS_ITEM (calitem));

    return TRUE;
}

static gboolean
e_calendar_item_button_release  (ECalendarItem  *calitem,
                 GdkEvent   *event)
{
    e_calendar_item_stop_selecting (calitem, event->button.time);
    return FALSE;
}


static gboolean
e_calendar_item_motion      (ECalendarItem  *calitem,
                 GdkEvent   *event)
{
    gint start_month, start_day, end_month, end_day, month_offset, day;
    gint tmp_month, tmp_day, days_in_selection;
    gboolean all_week, round_up_end = FALSE, round_down_start = FALSE;

    if (!calitem->selecting)
        return FALSE;

    if (!e_calendar_item_convert_position_to_day (calitem,
                              event->button.x,
                              event->button.y,
                              TRUE,
                              &month_offset, &day,
                              &all_week))
        return FALSE;

    if (day == -1)
        return FALSE;

    if (calitem->selection_dragging_end) {
        start_month = calitem->selection_real_start_month_offset;
        start_day = calitem->selection_real_start_day;
        end_month = month_offset;
        end_day = day;
    } else {
        start_month = month_offset;
        start_day = day;
        end_month = calitem->selection_real_start_month_offset;
        end_day = calitem->selection_real_start_day;
    }

    if (start_month > end_month || (start_month == end_month
                    && start_day > end_day)) {
        tmp_month = start_month;
        tmp_day = start_day;
        start_month = end_month;
        start_day = end_day;
        end_month = tmp_month;
        end_day = tmp_day;

        calitem->selection_dragging_end = !calitem->selection_dragging_end;
    }

    if (calitem->days_to_start_week_selection > 0) {
        days_in_selection = e_calendar_item_get_inclusive_days (calitem, start_month, start_day, end_month, end_day);
        if (days_in_selection >= calitem->days_to_start_week_selection) {
            round_down_start = TRUE;
            round_up_end = TRUE;
        }
    }

    /* If we are over a week number and we are dragging the end of the
       selection, we round up to the end of this week. */
    if (all_week && calitem->selection_dragging_end)
        round_up_end = TRUE;

    /* If the selection was started from a week number and we are dragging
       the start of the selection, we need to round up the end to include
       all of the original week selected. */
    if (calitem->selection_from_full_week
        && !calitem->selection_dragging_end)
            round_up_end = TRUE;

    /* Don't round up or down if we can't select a week or more. */
    if (calitem->max_days_selected < 7) {
        round_down_start = FALSE;
        round_up_end = FALSE;
    }

    if (round_up_end)
        e_calendar_item_round_up_selection (calitem, &end_month,
                            &end_day);
    if (round_down_start)
        e_calendar_item_round_down_selection (calitem, &start_month,
                              &start_day);


    /* Check we don't go over the maximum number of days to select. */
    if (calitem->selection_dragging_end) {
        e_calendar_item_check_selection_end (calitem,
                             start_month,
                             start_day,
                             &end_month,
                             &end_day);
    } else {
        e_calendar_item_check_selection_start (calitem,
                               &start_month,
                               &start_day,
                               end_month,
                               end_day);
    }

    if (start_month == calitem->selection_start_month_offset
        && start_day == calitem->selection_start_day
        && end_month == calitem->selection_end_month_offset
        && end_day == calitem->selection_end_day)
        return FALSE;

    calitem->selection_start_month_offset = start_month;
    calitem->selection_start_day = start_day;
    calitem->selection_end_month_offset = end_month;
    calitem->selection_end_day = end_day;

    gnome_canvas_item_request_update (GNOME_CANVAS_ITEM (calitem));

    return TRUE;
}


static void
e_calendar_item_check_selection_end (ECalendarItem  *calitem,
                     gint        start_month,
                     gint        start_day,
                     gint       *end_month,
                     gint       *end_day)
{
    gint year, month, max_month, max_day, days_in_month;

    if (calitem->max_days_selected <= 0)
        return;

    year = calitem->year;
    month = calitem->month + start_month;
    e_calendar_item_normalize_date (calitem, &year, &month);

    max_month = start_month;
    max_day = start_day + calitem->max_days_selected - 1;

    for (;;) {
        days_in_month = DAYS_IN_MONTH (year, month);
        if (max_day <= days_in_month)
            break;
        max_month++;
        month++;
        if (month == 12) {
            year++;
            month = 0;
        }
        max_day -= days_in_month;
    }

    if (*end_month > max_month) {
        *end_month = max_month;
        *end_day = max_day;
    } else if (*end_month == max_month && *end_day > max_day) {
        *end_day = max_day;
    }
}


static void
e_calendar_item_check_selection_start   (ECalendarItem  *calitem,
                     gint       *start_month,
                     gint       *start_day,
                     gint        end_month,
                     gint        end_day)
{
    gint year, month, min_month, min_day, days_in_month;

    if (calitem->max_days_selected <= 0)
        return;

    year = calitem->year;
    month = calitem->month + end_month;
    e_calendar_item_normalize_date (calitem, &year, &month);

    min_month = end_month;
    min_day = end_day - calitem->max_days_selected + 1;

    while (min_day <= 0) {
        min_month--;
        month--;
        if (month == -1) {
            year--;
            month = 11;
        }
        days_in_month = DAYS_IN_MONTH (year, month);
        min_day += days_in_month;
    }

    if (*start_month < min_month) {
        *start_month = min_month;
        *start_day = min_day;
    } else if (*start_month == min_month && *start_day < min_day) {
        *start_day = min_day;
    }
}


/* Converts a position within the item to a month & day.
   The month returned is 0 for the top-left month displayed.
   If the position is over the month heading -1 is returned for the day.
   If the position is over a week number the first day of the week is returned
   and entire_week is set to TRUE.
   It returns FALSE if the position is completely outside all months. */
static gboolean
e_calendar_item_convert_position_to_day (ECalendarItem  *calitem,
                     gint        event_x,
                     gint        event_y,
                     gboolean    round_empty_positions,
                     gint       *month_offset,
                     gint       *day,
                     gboolean   *entire_week)
{
    GnomeCanvasItem *item;
    GtkWidget *widget;
    GtkStyle *style;
    gint xthickness, ythickness, char_height;
    gint x, y, row, col, cells_x, cells_y, day_row, day_col;
    gint first_day_offset, days_in_month, days_in_prev_month;
    gint week_num_x1, week_num_x2;
    PangoFontDescription *font_desc;
    PangoContext *pango_context;
    PangoFontMetrics *font_metrics;

    item = GNOME_CANVAS_ITEM (calitem);
    widget = GTK_WIDGET (item->canvas);
    style = widget->style;

    font_desc = calitem->font_desc;
    if (!font_desc)
        font_desc = style->font_desc;
    pango_context = gtk_widget_create_pango_context (widget);
    font_metrics = pango_context_get_metrics (pango_context, font_desc,
                          pango_context_get_language (pango_context));

    char_height =
        PANGO_PIXELS (pango_font_metrics_get_ascent (font_metrics)) +
        PANGO_PIXELS (pango_font_metrics_get_descent (font_metrics));
    xthickness = style->xthickness;
    ythickness = style->ythickness;

    pango_font_metrics_unref (font_metrics);

    *entire_week = FALSE;

    x = event_x - xthickness - calitem->x_offset;
    y = event_y - ythickness;

    if (x < 0 || y < 0)
        return FALSE;

    row = y / calitem->month_height;
    col = x / calitem->month_width;

    if (row >= calitem->rows || col >= calitem->cols)
        return FALSE;

    *month_offset = row * calitem->cols + col;

    x = x % calitem->month_width;
    y = y % calitem->month_height;

    if (y < ythickness * 2 + E_CALENDAR_ITEM_YPAD_ABOVE_MONTH_NAME
        + char_height + E_CALENDAR_ITEM_YPAD_BELOW_MONTH_NAME) {
        *day = -1;
        return TRUE;
    }

    cells_y = ythickness * 2 + E_CALENDAR_ITEM_YPAD_ABOVE_MONTH_NAME
        + char_height + E_CALENDAR_ITEM_YPAD_BELOW_MONTH_NAME
        + E_CALENDAR_ITEM_YPAD_ABOVE_DAY_LETTERS + calitem->month_tpad
        + char_height + E_CALENDAR_ITEM_YPAD_BELOW_DAY_LETTERS + 1
        + E_CALENDAR_ITEM_YPAD_ABOVE_CELLS;
    y -= cells_y;
    if (y < 0)
        return FALSE;
    day_row = y / calitem->cell_height;
    if (day_row >= E_CALENDAR_ROWS_PER_MONTH)
        return FALSE;

    week_num_x1 = E_CALENDAR_ITEM_XPAD_BEFORE_WEEK_NUMBERS + calitem->month_lpad;

    if (calitem->show_week_numbers) {
        week_num_x2 = week_num_x1
            + calitem->max_week_number_digit_width * 2;
        if (x >= week_num_x1 && x < week_num_x2)
            *entire_week = TRUE;
        cells_x = week_num_x2 + E_CALENDAR_ITEM_XPAD_AFTER_WEEK_NUMBERS + 1;
    } else {
        cells_x = week_num_x1;
    }

    if (*entire_week) {
        day_col = 0;
    } else {
        cells_x += E_CALENDAR_ITEM_XPAD_BEFORE_CELLS;
        x -= cells_x;
        if (x < 0)
            return FALSE;
        day_col = x / calitem->cell_width;
        if (day_col >= E_CALENDAR_COLS_PER_MONTH)
            return FALSE;
    }

    *day = day_row * E_CALENDAR_COLS_PER_MONTH + day_col;

    e_calendar_item_get_month_info (calitem, row, col, &first_day_offset,
                    &days_in_month, &days_in_prev_month);
    if (*day < first_day_offset) {
        if (*entire_week || (row == 0 && col == 0)) {
            (*month_offset)--;
            *day = days_in_prev_month + 1 - first_day_offset
                + *day;
            return TRUE;
        } else if (round_empty_positions) {
            *day = first_day_offset;
        } else {
            return FALSE;
        }
    }

    *day -= first_day_offset - 1;

    if (*day > days_in_month) {
        if (row == calitem->rows - 1 && col == calitem->cols - 1) {
            (*month_offset)++;
            *day -= days_in_month;
            return TRUE;
        } else if (round_empty_positions) {
            *day = days_in_month;
        } else {
            return FALSE;
        }
    }

    return TRUE;
}


static void
e_calendar_item_get_month_info  (ECalendarItem  *calitem,
                 gint        row,
                 gint        col,
                 gint       *first_day_offset,
                 gint       *days_in_month,
                 gint       *days_in_prev_month)
{
    gint year, month, start_weekday, first_day_of_month;
    struct tm tmp_tm = { 0 };

    month = calitem->month + row * calitem->cols + col;
    year = calitem->year + month / 12;
    month = month % 12;

    *days_in_month = DAYS_IN_MONTH (year, month);
    if (month == 0)
        *days_in_prev_month = DAYS_IN_MONTH (year - 1, 11);
    else
        *days_in_prev_month = DAYS_IN_MONTH (year, month - 1);

    tmp_tm.tm_year = year - 1900;
    tmp_tm.tm_mon = month;
    tmp_tm.tm_mday = 1;
    tmp_tm.tm_isdst = -1;
    mktime (&tmp_tm);

    /* Convert to 0 (Monday) to 6 (Sunday). */
    start_weekday = (tmp_tm.tm_wday + 6) % 7;

    first_day_of_month = (start_weekday + 7 - calitem->week_start_day) % 7;

    if (row == 0 && col == 0 && first_day_of_month == 0)
        *first_day_offset = 7;
    else
        *first_day_offset = first_day_of_month;
}


void
e_calendar_item_get_first_month(ECalendarItem   *calitem,
                gint        *year,
                gint        *month)
{
    *year = calitem->year;
    *month = calitem->month;
}


/* This also handles values of month < 0 or > 11 by updating the year. */
void
e_calendar_item_set_first_month(ECalendarItem   *calitem,
                gint         year,
                gint         month)
{
    gint new_year, new_month, months_diff, num_months;
    gint old_days_in_selection, new_days_in_selection;

    new_year = year;
    new_month = month;
    e_calendar_item_normalize_date  (calitem, &new_year, &new_month);

    if (calitem->year == new_year && calitem->month == new_month)
        return;

    /* Update the selection. */
    num_months = calitem->rows * calitem->cols;
    months_diff = (new_year - calitem->year) * 12
        + new_month - calitem->month;

    if (calitem->selection_set) {
        if (!calitem->move_selection_when_moving
            || (calitem->selection_start_month_offset - months_diff >= 0
            && calitem->selection_end_month_offset - months_diff < num_months)) {
            calitem->selection_start_month_offset -= months_diff;
            calitem->selection_end_month_offset -= months_diff;
            calitem->selection_real_start_month_offset -= months_diff;

            calitem->year = new_year;
            calitem->month = new_month;
        } else {
            old_days_in_selection = e_calendar_item_get_inclusive_days (calitem, calitem->selection_start_month_offset, calitem->selection_start_day, calitem->selection_end_month_offset, calitem->selection_end_day);
            
            /* Make sure the selection will be displayed. */
            if (calitem->selection_start_month_offset < 0
                || calitem->selection_start_month_offset >= num_months) {
                calitem->selection_end_month_offset -= calitem->selection_start_month_offset;
                calitem->selection_start_month_offset = 0;
            }

            /* We want to ensure that the same number of days are
               selected after we have moved the selection. */
            calitem->year = new_year;
            calitem->month = new_month;

            e_calendar_item_ensure_valid_day (calitem, &calitem->selection_start_month_offset, &calitem->selection_start_day);
            e_calendar_item_ensure_valid_day (calitem, &calitem->selection_end_month_offset, &calitem->selection_end_day);

            if (calitem->round_selection_when_moving) {
                e_calendar_item_round_down_selection (calitem, &calitem->selection_start_month_offset, &calitem->selection_start_day);
            }

            new_days_in_selection = e_calendar_item_get_inclusive_days (calitem, calitem->selection_start_month_offset, calitem->selection_start_day, calitem->selection_end_month_offset, calitem->selection_end_day);

            if (old_days_in_selection != new_days_in_selection)
                e_calendar_item_add_days_to_selection (calitem, old_days_in_selection - new_days_in_selection);

            /* Flag that we need to emit the "selection_changed"
               signal. We don't want to emit it here since setting
               the "year" and "month" args would result in 2
               signals emitted. */
            calitem->selection_changed = TRUE;
        }
    } else {
        calitem->year = new_year;
        calitem->month = new_month;
    }

    e_calendar_item_date_range_changed (calitem);
    gnome_canvas_item_request_update (GNOME_CANVAS_ITEM (calitem));
}

/* Get the maximum number of days selectable */
gint
e_calendar_item_get_max_days_sel       (ECalendarItem   *calitem)
{
    return calitem->max_days_selected;
}


/* Set the maximum number of days selectable */
void     
e_calendar_item_set_max_days_sel       (ECalendarItem   *calitem,
                    gint             days)
{
    calitem->max_days_selected = MAX (0, days);
    gnome_canvas_item_request_update (GNOME_CANVAS_ITEM (calitem));
}


/* Get the maximum number of days before whole weeks are selected */
gint     
e_calendar_item_get_days_start_week_sel(ECalendarItem   *calitem)
{
    return calitem->days_to_start_week_selection;
}


/* Set the maximum number of days before whole weeks are selected */
void     
e_calendar_item_set_days_start_week_sel(ECalendarItem   *calitem,
                    gint            days)
{
    calitem->days_to_start_week_selection = days;
}

gboolean 
e_calendar_item_get_display_popup      (ECalendarItem   *calitem)
{
    return calitem->display_popup;
}


void     
e_calendar_item_set_display_popup      (ECalendarItem   *calitem,
                    gboolean        display)
{
    calitem->display_popup = display;
}


/* This will make sure that the given year & month are valid, i.e. if month
   is < 0 or > 11 the year and month will be updated accordingly. */
void
e_calendar_item_normalize_date  (ECalendarItem  *calitem,
                 gint       *year,
                 gint       *month)
{
    if (*month >= 0) {
        *year += *month / 12;
        *month = *month % 12;
    } else {
        *year += *month / 12 - 1;
        *month = *month % 12;
        if (*month != 0)
            *month += 12;
    }
}


/* Adds or subtracts days from the selection. It is used when we switch months
   and the selection extends past the end of a month but we want to keep the
   number of days selected the same. days should not be more than 30. */
static void
e_calendar_item_add_days_to_selection   (ECalendarItem  *calitem,
                     gint        days)
{
    gint year, month, days_in_month;

    year = calitem->year;
    month = calitem->month + calitem->selection_end_month_offset;
    e_calendar_item_normalize_date (calitem, &year, &month);

    calitem->selection_end_day += days;
    if (calitem->selection_end_day <= 0) {
        month--;
        e_calendar_item_normalize_date (calitem, &year, &month);
        calitem->selection_end_month_offset--;
        calitem->selection_end_day += DAYS_IN_MONTH (year, month);
    } else {
        days_in_month = DAYS_IN_MONTH (year, month);
        if (calitem->selection_end_day > days_in_month) {
            calitem->selection_end_month_offset++;
            calitem->selection_end_day -= days_in_month;
        }
    }
}


/* Gets the range of dates actually shown. Months are 0 to 11.
   This also includes the last days of the previous month and the first days
   of the following month, which are normally shown in gray.
   It returns FALSE if no dates are currently shown. */
gboolean
e_calendar_item_get_date_range  (ECalendarItem  *calitem,
                 gint       *start_year,
                 gint       *start_month,
                 gint       *start_day,
                 gint       *end_year,
                 gint       *end_month,
                 gint       *end_day)
{
    gint first_day_offset, days_in_month, days_in_prev_month;

    if (calitem->rows == 0 || calitem->cols == 0)
        return FALSE;

    /* Calculate the first day shown. This will be one of the greyed-out
       days before the first full month begins. */
    e_calendar_item_get_month_info (calitem, 0, 0, &first_day_offset,
                    &days_in_month, &days_in_prev_month);
    *start_year = calitem->year;
    *start_month = calitem->month - 1;
    if (*start_month == -1) {
        (*start_year)--;
        *start_month = 11;
    }
    *start_day = days_in_prev_month + 1 - first_day_offset;


    /* Calculate the last day shown. This will be one of the greyed-out
       days after the last full month ends. */
    e_calendar_item_get_month_info (calitem, calitem->rows - 1,
                    calitem->cols - 1, &first_day_offset,
                    &days_in_month, &days_in_prev_month);
    *end_month = calitem->month + calitem->rows * calitem->cols;
    *end_year = calitem->year + *end_month / 12;
    *end_month %= 12;
    *end_day = E_CALENDAR_ROWS_PER_MONTH * E_CALENDAR_COLS_PER_MONTH
        - first_day_offset - days_in_month;

    return TRUE;
}


/* Simple way to mark days so they appear bold.
   A more flexible interface may be added later. */
void
e_calendar_item_clear_marks (ECalendarItem  *calitem)
{
    GnomeCanvasItem *item;

    item = GNOME_CANVAS_ITEM (calitem);

    g_free (calitem->styles);
    calitem->styles = NULL;

    gnome_canvas_request_redraw (item->canvas, item->x1, item->y1,
                     item->x2, item->y2);
}


void
e_calendar_item_mark_day    (ECalendarItem  *calitem,
                 gint        year,
                 gint        month,
                 gint        day,
                 guint8      day_style)
{
    gint month_offset;

    month_offset = (year - calitem->year) * 12 + month - calitem->month;
    if (month_offset < -1 || month_offset > calitem->rows * calitem->cols)
        return;

    if (!calitem->styles)
        calitem->styles = g_new0 (guint8, (calitem->rows * calitem->cols + 2) * 32);

    calitem->styles[(month_offset + 1) * 32 + day] = day_style;

    gnome_canvas_item_request_update (GNOME_CANVAS_ITEM (calitem));
}


void
e_calendar_item_mark_days   (ECalendarItem  *calitem,
                 gint        start_year,
                 gint        start_month,
                 gint        start_day,
                 gint        end_year,
                 gint        end_month,
                 gint        end_day,
                 guint8      day_style)
{
    gint month_offset, end_month_offset, day;

    month_offset = (start_year - calitem->year) * 12 + start_month
        - calitem->month;
    day = start_day;
    if (month_offset > calitem->rows * calitem->cols)
        return;
    if (month_offset < -1) {
        month_offset = -1;
        day = 1;
    }

    end_month_offset = (end_year - calitem->year) * 12 + end_month
        - calitem->month;
    if (end_month_offset < -1)
        return;
    if (end_month_offset > calitem->rows * calitem->cols) {
        end_month_offset = calitem->rows * calitem->cols;
        end_day = 31;
    }

    if (month_offset > end_month_offset)
        return;

    if (!calitem->styles)
        calitem->styles = g_new0 (guint8, (calitem->rows * calitem->cols + 2) * 32);

    for (;;) {
        if (month_offset == end_month_offset && day > end_day)
            break;

        if (month_offset < -1 || month_offset > calitem->rows * calitem->cols)
            g_warning ("Bad month offset: %i\n", month_offset);
        if (day < 1 || day > 31)
            g_warning ("Bad day: %i\n", day);

#if 0
        g_print ("Marking Month:%i Day:%i\n", month_offset, day);
#endif
        calitem->styles[(month_offset + 1) * 32 + day] = day_style;

        day++;
        if (day == 32) {
            month_offset++;
            day = 1;
            if (month_offset > end_month_offset)
                break;
        }
    }

    gnome_canvas_item_request_update (GNOME_CANVAS_ITEM (calitem));
}


/* Rounds up the given day to the end of the week. */
static void
e_calendar_item_round_up_selection  (ECalendarItem  *calitem,
                     gint       *month_offset,
                     gint       *day)
{
    gint year, month, weekday, days, days_in_month;
    struct tm tmp_tm = { 0 };

    year = calitem->year;
    month = calitem->month + *month_offset;
    e_calendar_item_normalize_date (calitem, &year, &month);

    tmp_tm.tm_year = year - 1900;
    tmp_tm.tm_mon = month;
    tmp_tm.tm_mday = *day;
    tmp_tm.tm_isdst = -1;
    mktime (&tmp_tm);

    /* Convert to 0 (Monday) to 6 (Sunday). */
    weekday = (tmp_tm.tm_wday + 6) % 7;

    /* Calculate how many days to the end of the row. */
    days = (calitem->week_start_day + 6 - weekday) % 7;

    *day += days;
    days_in_month = DAYS_IN_MONTH (year, month);
    if (*day > days_in_month) {
        (*month_offset)++;
        *day -= days_in_month;
    }
}


/* Rounds down the given day to the start of the week. */
static void
e_calendar_item_round_down_selection    (ECalendarItem  *calitem,
                     gint       *month_offset,
                     gint       *day)
{
    gint year, month, weekday, days, days_in_month;
    struct tm tmp_tm = { 0 };

    year = calitem->year;
    month = calitem->month + *month_offset;
    e_calendar_item_normalize_date (calitem, &year, &month);

    tmp_tm.tm_year = year - 1900;
    tmp_tm.tm_mon = month;
    tmp_tm.tm_mday = *day;
    tmp_tm.tm_isdst = -1;
    mktime (&tmp_tm);

    /* Convert to 0 (Monday) to 6 (Sunday). */
    weekday = (tmp_tm.tm_wday + 6) % 7;

    /* Calculate how many days to the start of the row. */
    days = (weekday + 7 - calitem->week_start_day) % 7;

    *day -= days;
    if (*day <= 0) {
        month--;
        if (month == -1) {
            year--;
            month = 11;
        }
        days_in_month = DAYS_IN_MONTH (year, month);
        (*month_offset)--;
        *day += days_in_month;
    }
}


static gint
e_calendar_item_get_inclusive_days  (ECalendarItem  *calitem,
                     gint        start_month_offset,
                     gint        start_day,
                     gint        end_month_offset,
                     gint        end_day)
{
    gint start_year, start_month, end_year, end_month, days = 0;

    start_year = calitem->year;
    start_month = calitem->month + start_month_offset;
    e_calendar_item_normalize_date (calitem, &start_year, &start_month);

    end_year = calitem->year;
    end_month = calitem->month + end_month_offset;
    e_calendar_item_normalize_date (calitem, &end_year, &end_month);

    while (start_year < end_year || start_month < end_month) {
        days += DAYS_IN_MONTH (start_year, start_month);
        start_month++;
        if (start_month == 12) {
            start_year++;
            start_month = 0;
        }
    }

    days += end_day - start_day + 1;

    return days;
}


/* If the day is off the end of the month it is set to the last day of the
   month. */
static void
e_calendar_item_ensure_valid_day    (ECalendarItem  *calitem,
                     gint       *month_offset,
                     gint       *day)
{
    gint year, month, days_in_month;

    year = calitem->year;
    month = calitem->month + *month_offset;
    e_calendar_item_normalize_date (calitem, &year, &month);

    days_in_month = DAYS_IN_MONTH (year, month);
    if (*day > days_in_month)
        *day = days_in_month;
}


gboolean
e_calendar_item_get_selection       (ECalendarItem  *calitem,
                     GDate      *start_date,
                     GDate      *end_date)
{
    gint start_year, start_month, start_day;
    gint end_year, end_month, end_day;

    g_date_clear (start_date, 1);
    g_date_clear (end_date, 1);

    if (!calitem->selection_set)
        return FALSE;

    start_year = calitem->year;
    start_month = calitem->month + calitem->selection_start_month_offset;
    e_calendar_item_normalize_date (calitem, &start_year, &start_month);
    start_day = calitem->selection_start_day;

    end_year = calitem->year;
    end_month = calitem->month + calitem->selection_end_month_offset;
    e_calendar_item_normalize_date (calitem, &end_year, &end_month);
    end_day = calitem->selection_end_day;

    g_date_set_dmy (start_date, start_day, start_month + 1, start_year);
    g_date_set_dmy (end_date, end_day, end_month + 1, end_year);

    return TRUE;
}


static void
e_calendar_item_set_selection_if_emission (ECalendarItem    *calitem,
                       GDate        *start_date,
                       GDate        *end_date,
                       gboolean emission)
{
    gint start_year, start_month, start_day;
    gint end_year, end_month, end_day;
    gint new_start_month_offset, new_start_day;
    gint new_end_month_offset, new_end_day;
    gboolean need_update;

    g_return_if_fail (E_IS_CALENDAR_ITEM (calitem));

    /* If start_date is NULL, we clear the selection without changing the
       month shown. */
    if (start_date == NULL) {
        calitem->selection_set = FALSE;
        calitem->selection_changed = TRUE;
        e_calendar_item_queue_signal_emission (calitem);
        gnome_canvas_item_request_update (GNOME_CANVAS_ITEM (calitem));
        return;
    }

    if (end_date == NULL)
        end_date = start_date;

    g_return_if_fail (g_date_compare (start_date, end_date) <= 0);

    start_year = g_date_get_year (start_date);
    start_month = g_date_get_month (start_date) - 1;
    start_day = g_date_get_day (start_date);
    end_year = g_date_get_year (end_date);
    end_month = g_date_get_month (end_date) - 1;
    end_day = g_date_get_day (end_date);

    need_update = e_calendar_item_ensure_days_visible (calitem,
                               start_year,
                               start_month,
                               start_day,
                               end_year,
                               end_month,
                               end_day,
                               emission);

    new_start_month_offset = (start_year - calitem->year) * 12
        + start_month - calitem->month;
    new_start_day = start_day;

    /* This may go outside the visible months, but we don't care. */
    new_end_month_offset = (end_year - calitem->year) * 12
        + end_month - calitem->month;
    new_end_day = end_day;


    if (!calitem->selection_set
        || calitem->selection_start_month_offset != new_start_month_offset
        || calitem->selection_start_day != new_start_day
        || calitem->selection_end_month_offset != new_end_month_offset
        || calitem->selection_end_day != new_end_day) {
        need_update = TRUE;
        if (emission) {
            calitem->selection_changed = TRUE;
            e_calendar_item_queue_signal_emission (calitem);
        }
        calitem->selection_set = TRUE;
        calitem->selection_start_month_offset = new_start_month_offset;
        calitem->selection_start_day = new_start_day;
        calitem->selection_end_month_offset = new_end_month_offset;
        calitem->selection_end_day = new_end_day;

        calitem->selection_real_start_month_offset = new_start_month_offset;
        calitem->selection_real_start_day = new_start_day;
        calitem->selection_from_full_week = FALSE;
    }

    if (need_update)
        gnome_canvas_item_request_update (GNOME_CANVAS_ITEM (calitem));
}

void
e_calendar_item_set_selection (ECalendarItem    *calitem,
                   GDate        *start_date,
                   GDate        *end_date)
{
    /* If the user is in the middle of a selection, we must abort it. */
    if (calitem->selecting) {
        gnome_canvas_item_ungrab (GNOME_CANVAS_ITEM (calitem),
                      GDK_CURRENT_TIME);
        calitem->selecting = FALSE;
    }

    e_calendar_item_set_selection_if_emission (calitem,
                           start_date, end_date,
                           TRUE);
}

/* This tries to ensure that the given time range is visible. If the range
   given is longer than we can show, only the start of it will be visible.
   Note that this will not update the selection. That should be done somewhere
   else. It returns TRUE if the visible range has been changed. */
static gboolean
e_calendar_item_ensure_days_visible (ECalendarItem  *calitem,
                     gint        start_year,
                     gint        start_month,
                     gint        start_day,
                     gint        end_year,
                     gint        end_month,
                     gint        end_day,
                     gboolean emission)
{
    gint current_end_year, current_end_month;
    gint months_shown, months;
    gint first_day_offset, days_in_month, days_in_prev_month;
    gboolean need_update = FALSE;

    months_shown = calitem->rows * calitem->cols;
    months = (end_year - start_year) * 12 + end_month - start_month;

    /* Calculate the range of months currently displayed. */
    current_end_year = calitem->year;
    current_end_month = calitem->month + months_shown - 1;
    e_calendar_item_normalize_date (calitem, &current_end_year,
                    &current_end_month);

    /* Try to ensure that the end month is shown. */
    if ((end_year == current_end_year + 1 && current_end_month == 11 && end_month == 0) ||
        (end_year == current_end_year && end_month == current_end_month + 1)) {
        /* See if the end of the selection will fit in the
           leftover days of the month after the last one shown. */
        calitem->month += (months_shown - 1);
        e_calendar_item_normalize_date (calitem, &calitem->year,
                        &calitem->month);
        
        e_calendar_item_get_month_info (calitem, 0, 0,
                        &first_day_offset,
                        &days_in_month,
                        &days_in_prev_month);

        if (end_day >= E_CALENDAR_ROWS_PER_MONTH * E_CALENDAR_COLS_PER_MONTH - 
            first_day_offset - days_in_month) {
            need_update = TRUE;

            calitem->year = end_year;
            calitem->month = end_month - months_shown + 1;
        } else {
            calitem->month -= (months_shown - 1);
        }

        e_calendar_item_normalize_date (calitem, &calitem->year,
                        &calitem->month);
    }
    else if (end_year > current_end_year ||
         (end_year == current_end_year && end_month > current_end_month)) {
        /* The selection will definitely not fit in the leftover days
         * of the month after the last one shown. */
        need_update = TRUE;

        calitem->year = end_year;
        calitem->month = end_month - months_shown + 1;

        e_calendar_item_normalize_date (calitem, &calitem->year,
                        &calitem->month);
    }

    /* Now try to ensure that the start month is shown. We do this after
       the end month so that the start month will always be shown. */
    if (start_year < calitem->year
        || (start_year == calitem->year
        && start_month < calitem->month)) {
        need_update = TRUE;

        /* First we see if the start of the selection will fit in the
           leftover days of the month before the first one shown. */
        calitem->year = start_year;
        calitem->month = start_month + 1;
        e_calendar_item_normalize_date (calitem, &calitem->year,
                        &calitem->month);

        e_calendar_item_get_month_info (calitem, 0, 0,
                        &first_day_offset,
                        &days_in_month,
                        &days_in_prev_month);

        if (start_day <= days_in_prev_month - first_day_offset) {
            calitem->year = start_year;
            calitem->month = start_month;
        }
    }

    if (need_update && emission)
        e_calendar_item_date_range_changed (calitem);

    return need_update;
}


static void
e_calendar_item_show_popup_menu     (ECalendarItem  *calitem,
                     GdkEventButton *event,
                     gint        month_offset)
{
    GtkWidget *menu, *submenu, *menuitem, *label;
    gint year, month;
    gchar buffer[64];
    struct tm tmp_tm;

    menu = gtk_menu_new ();

    for (year = calitem->year - 2; year <= calitem->year + 2; year++) {
        g_snprintf (buffer, 64, "%i", year);
        menuitem = gtk_menu_item_new_with_label (buffer);
        gtk_widget_show (menuitem);
        gtk_container_add (GTK_CONTAINER (menu), menuitem);

        submenu = gtk_menu_new ();
        gtk_menu_item_set_submenu (GTK_MENU_ITEM (menuitem), submenu);

        g_object_set_data(G_OBJECT(submenu), "year",
                     GINT_TO_POINTER (year));
        g_object_set_data(G_OBJECT(submenu), "month_offset",
                     GINT_TO_POINTER (month_offset));

        for (month = 0; month < 12; month++) {
            memset (&tmp_tm, 0, sizeof (tmp_tm));
            tmp_tm.tm_year = year - 1900;
            tmp_tm.tm_mon = month;
            tmp_tm.tm_mday = 1;
            tmp_tm.tm_isdst = -1;
            mktime (&tmp_tm);
            e_utf8_strftime (buffer, sizeof (buffer), "%B", &tmp_tm);

            menuitem = gtk_menu_item_new ();
            gtk_widget_show (menuitem);
            gtk_container_add (GTK_CONTAINER (submenu), menuitem);

            label = gtk_label_new (buffer);
            gtk_misc_set_alignment (GTK_MISC (label), 0.0, 0.5);
            gtk_widget_show (label);
            gtk_container_add (GTK_CONTAINER (menuitem), label);

            g_object_set_data(G_OBJECT(menuitem), "month",
                         GINT_TO_POINTER (month));

            g_signal_connect((menuitem), "activate",
                        G_CALLBACK (e_calendar_item_on_menu_item_activate), calitem);
        }
    }

    /* Run the menu modal so we can destroy it after. */
    g_signal_connect((menu), "deactivate",
                G_CALLBACK (gtk_main_quit), NULL);
    gtk_menu_popup (GTK_MENU (menu), NULL, NULL,
            e_calendar_item_position_menu, calitem,
            event->button, event->time);
    gtk_grab_add (menu);
    gtk_main ();
    gtk_grab_remove (menu);
    gtk_widget_destroy (menu);
}


static void
e_calendar_item_on_menu_item_activate   (GtkWidget  *menuitem,
                     ECalendarItem  *calitem)
{
    gint year, month_offset, month;

    year = GPOINTER_TO_INT (g_object_get_data(G_OBJECT(menuitem->parent), "year"));
    month_offset = GPOINTER_TO_INT (g_object_get_data(G_OBJECT(menuitem->parent), "month_offset"));
    month = GPOINTER_TO_INT (g_object_get_data(G_OBJECT(menuitem), "month"));

    month -= month_offset;
    e_calendar_item_normalize_date (calitem, &year, &month);
    e_calendar_item_set_first_month (calitem, year, month);
}


static void
e_calendar_item_position_menu   (GtkMenu            *menu,
                 gint               *x,
                 gint               *y,
                 gboolean           *push_in,
                 gpointer            user_data)
{
    GtkRequisition requisition;
    gint screen_width, screen_height;

    gtk_widget_get_child_requisition (GTK_WIDGET (menu), &requisition);

    *x -= 2;
    *y -= requisition.height / 2;

    screen_width = gdk_screen_width ();
    screen_height = gdk_screen_height ();

    *x = CLAMP (*x, 0, screen_width - requisition.width);
    *y = CLAMP (*y, 0, screen_height - requisition.height);
}


/* Sets the function to call to get the colors to use for a particular day. */
void
e_calendar_item_set_style_callback  (ECalendarItem  *calitem,
                     ECalendarItemStyleCallback cb,
                     gpointer    data,
                     GtkDestroyNotify destroy)
{
    g_return_if_fail (E_IS_CALENDAR_ITEM (calitem));

    if (calitem->style_callback_data && calitem->style_callback_destroy)
        (*calitem->style_callback_destroy) (calitem->style_callback_data);

    calitem->style_callback = cb;
    calitem->style_callback_data = data;
    calitem->style_callback_destroy = destroy;
}


static void
e_calendar_item_date_range_changed  (ECalendarItem  *calitem)
{
    g_free (calitem->styles);
    calitem->styles = NULL;
    calitem->date_range_changed = TRUE;
    e_calendar_item_queue_signal_emission (calitem);
}


static void
e_calendar_item_queue_signal_emission   (ECalendarItem  *calitem)
{
    if (calitem->signal_emission_idle_id == 0) {
        calitem->signal_emission_idle_id = g_idle_add_full (G_PRIORITY_HIGH, e_calendar_item_signal_emission_idle_cb, calitem, NULL);
    }
}


static gboolean
e_calendar_item_signal_emission_idle_cb (gpointer data)
{
    ECalendarItem *calitem;

    g_return_val_if_fail (E_IS_CALENDAR_ITEM (data), FALSE);

    GDK_THREADS_ENTER ();

    calitem = E_CALENDAR_ITEM (data);

    calitem->signal_emission_idle_id = 0;

    /* We ref the calitem & check in case it gets destroyed, since we
       were getting a free memory write here. */
    g_object_ref((calitem));

    if (calitem->date_range_changed) {
        calitem->date_range_changed = FALSE;
        gtk_signal_emit (GTK_OBJECT (calitem),
                 e_calendar_item_signals[DATE_RANGE_CHANGED]);
    }

    if (calitem->selection_changed) {
        calitem->selection_changed = FALSE;
        gtk_signal_emit (GTK_OBJECT (calitem),
                 e_calendar_item_signals[SELECTION_CHANGED]);
    }

    g_object_unref((calitem));

    GDK_THREADS_LEAVE ();
    return FALSE;
}


/* Sets a callback to use to get the current time. This is useful if the
   application needs to use its own timezone data rather than rely on the
   Unix timezone. */
void
e_calendar_item_set_get_time_callback   (ECalendarItem  *calitem,
                     ECalendarItemGetTimeCallback cb,
                     gpointer    data,
                     GtkDestroyNotify destroy)
{
    g_return_if_fail (E_IS_CALENDAR_ITEM (calitem));

    if (calitem->time_callback_data && calitem->time_callback_destroy)
        (*calitem->time_callback_destroy) (calitem->time_callback_data);

    calitem->time_callback = cb;
    calitem->time_callback_data = data;
    calitem->time_callback_destroy = destroy;
}